Yes. I use it so I can Cover -> Snap Shot -> Move -> Followthrough which means you are only stopped for about half a second. The advantage is mobility, or damage at the beginning of the global cooldown rather then the end.

It's been tested, weaker versions of your CD and CG are overwritten when you cast the more powerful ones. You will only ever get Cull to interact with 2 DoT debuffs.

To be fair, I used to be a proponent of how terrible Rapid Fire is. It does look underwhelming when you look at it and when used without Target Acquired it's terrible. However after using it and running the math on it via Tibbel's spreadsheet, I realized a Rapid Fire combo is more damage then you could get if you could theoretically Cull twice in a row. Even the more cooldown limited Hybrid Lethality combo doesn't achieve the same results. Rapid Fire Combo TA -> SoS -> RF -> SoS -> SoS -> RS Ambush -> FT ~9.5 seconds with ~2450 DPS Theoretical Double Cull CD -> WB -> CG -> TA -> Cull -> *Cull ~9.0 seconds with ~2293 DPS Lethality Cull Combo CD -> WB -> CG -> TA -> Cull -> SoS ~9.0 seconds with ~2115 DPS Hybrid Cull Combo CD -> CG -> EP -> TA -> Cull -> SoS ~9.0 seconds with ~2283 DPS Engineering SoS Combo IP -> EP -> TA -> SoS -> Ambush -> Snipe -> Snipe ~9.8 seconds with ~2371 DPS Rapid Fire is a lot better then most people seem to think. The only trouble is getting off 3 successive SoS in the 6-7 seconds of staying completely still. It's easier with Entrench of course, but any opponent you knows what you are doing better be LoS'ing or popping a Defensive cooldown or else they are dead by the end of it. Not to mention, come patch 1.2 Marksman has Sniper's Volley and Lethality loses a little damage from Cull's energy damage component. Note: I did a little mucking around with the rotations to see what would be their best combination. I'm sure there could be even more improvements, but I didn't want to spend all day working on rotations I don't plan on using.

If you've checked Tibbel's math over at mmo-mechanics.com dealing with the new Sniper's Volley, you'd know that only 1 point in Sniper Volley is really low. (Unless you plan on dumping something else.) The new talent for 60% reduction in aoe damage is pretty awesome, but I personally tried it for a few hours and never once even felt it was useful. The difference between 1 pt and 3 pt Sniper Volley to me was night and day for reliability. Getting a Sniper Volley to proc early on in a Rapid Fire combo gave me incredible damage. Ah, i'm aiming at getting Slip Away since I enjoy the 30s cooldown and speed boost on Debilitate more then the extra points in Engineering. Really it's a personal choice there, I love those 5 points in Engineering, but I often get to use Debilitate on cooldown when it's on a 30s timer. It makes solo'ing Maruaders, Assassins, and Operatives a lot easier if I end up being forced to do so and can let me escape many sticky situations I wouldn't have been able to before. Alacrity does reduce the global cooldown on an activation time ability if it brings it's activation time under 1.5s. It's most helpful for SoS and it's okay for RS Ambush and Snipe, but again it doesn't really have any effect on sustained damage. The most optimal time it's used is in a Rapid Fire combo where it has nearly full effect. Since it's your highest period of DPS over such a long duration, it's not a bad investment.

I personally didn't like the Hybrid Lethality/Engineering build before 1.2, but I did acknowledge it's strength in retaining energy. With Weakening Blast not costing any energy and a dispel protection talent up there you'd be absolutely crazy to play without a full Lethality build. At least in PvP. A simple CD -> WB -> CG -> Cull combo does not put you into the lower energy bracket when combined with Energy Tanks. In fact, with a 50% DoT crit rate you will end this combo with ~93/110 Energy. You just did your burst combo that normally places you at ~72/110 energy. I think people are severely underestimating what can be done here with a full Lethality combo costing 15 less energy since it keeps you out of the lower energy bracket the entire time.

Shield Probe grants us around 1500 - 2000 HP in an absorb bubble. It effects all abilities that hit us in the same way. While it technically blocks every single damage spell out there, overflow damage is still inflicted upon us. Effectively, using Shield Probe is giving yourself a very small heal that can go above your maximum hp.

You are right that a lot of things in SWTOR need to be fine tuned. However if you played at WoW's launch then you'd have remembered there were a heck of a lot more issues there then here - there wasn't even a PvP system to begin with at launch. As a Rogue vanish hardly ever worked and as a Mage I had to be careful where to blink because I'd often fall through the ground. Game Development isn't nearly as easy as you seem to think either. Especially in the case of an MMO. I'm sure they were aware of it, but they have mountains of issues to address and I highly doubt that a convenience feature was on a higher priority then making it so someone with a certain video card could even play the game. MMO's always start rough. SWTOR is the least rough I've ever seen at lunch, but it still has it's issues. Over time convenience is added and it gains all of it's features.

Probably not that much. I just enjoy having 4% Alacrity more then 10% extra Shiv damage. Alacrity has an effect on lowering the burst period (thus raising the burst DPS) of Series of Shots, Snipe, and Ambush which makes it useful in PvP even if it's extremely poor for sustained DPS. Really it improves the burst combo of TA -> SoS -> RF -> SoS -> SoS -> Ambush -> FT by ~4% since the entire combo up til the end is activation times. Marksman won't change that much. Personally I'll gain the 2 talent points out of Imperial Assassin, remove the 1 point from Imperial Demarcation, and place 3 talent points into Sniper's Volley for patch 1.2 I effectively just gain the new Sniper's Volley. Although, the new 31 pt Lethality build is looking absolutely wonderful, but then again this is a Marksman PvP thread.

Indeed, anyone that understands Lethality knows if you interrupt the Cull then you basically shut down their entire talent spec for 9 seconds. A good one will still use Series of Shots and Ambush in it's place, but it's still a severe damper on their damage output.

The easiest way to tell is by looking at their tooltip and by noticing what color of damage they deal. If a tooltip mentions weapon damage and the damage type is white, it's a Ranged attack. If a tooltip mentions a specific type of damage and the damage type is yelllow, it's a Tech attack. Marksman Snipers have a lot of Ranged attacks, and Lethality Snipers have a lot of Tech. In the end, you will always use both.

You should always at least try to use Cover before a Cull. The immunities it provides are invaluable. Not like you are moving around while using Cull anyway.

It's a matter of opinion which is better, since each one would be better in differing situations. Hybrid Marksman Full Marksman My Own Variation

Cunning is better. Check out Tibbel's spreadsheet on Sithwarrior.com and get your own personalized stat weights.

Most of that post was intended to help the OP. Not intended to be an entire post in response to your own. Sorry for the confusion. Indeed, excellent point. Was not my rotation, and no I don't think it would work as was advertised. It'd take a lot more then that, but it won't merely scratch em' and do only 20% health in damage. Telling someone you have no chance isn't going to help him unless you intend on trying to convince them to re-roll - which isn't the type of help he asked for. It's not hopeless against a Darkness Assassin. Not as bad as you all seem to think. You don't have to beat them 1v1 to be victorious. Preventing the entire situation in the first place with proper positioning is the best solution. Anyway, I think the OP has enough to help him with this - so I'm going to quit arguing with all of you about it in here.

Deflection is a translucent purple shield for the Sith Assassin, and it's a pearl white translucent shield for the Jedi Shadow. Both are rather difficult to see, although the Shadow one is a pain. I most often detect it by being deflected and then checking their buffs quick.