You're missing a part of the point, it's not only about being able to stomp*, but also about challenge: solo challenge. Taking on 4-man heroics and flashpoints by yourself, before you outlevel them more than a handful of levels, provides all sorts of great gameplay that you don't need to find a cooperative group in order to enjoy. If you can, name any other parts of the game that allows for the following:
- Can be done solo.
- Requires you to properly gear your character and your companion.
- Often requires you to get familiar with attacks/abilities of your opponent, as well as plan/time usage of your own abilities.
- Often requires you to use everything you have in your arsenal in order to prevail. Stims, adrenals, medpacks, legacy abilities, direct control of companion abilities, etc.
Currently, all game content that I can think of that presents this kind of challenge is designed for more than one player, which I always found odd. Taking it on solo may not have been intended, but it's certanly been possible, and it's certainly been a lot of fun.
* = though I do feel level scaling takes away from immersion, as mentioned. If the Korriban wastes are as difficult to survive at level 60 as at level 5, it just serves to negate any feeling of character growth.