First off if we pass judgement by what we see(i mean literally visual performance) i have to agree with the creator of this Thread that Kotor1, Kotor2TSL and SWTOR - will eat, swallow and sh*t the characters from original movies from I to VII
BUT....
Evolution mate, Evolution....
Right back in the day when they released the first SW movie "A new Hope" - the universe of Star Wars, was still very young and undeveloped but as we can see - looking back in time chronologically, from the very first Star Wars released material until now we witness(and here i will repeat myself) EVOLUTION and the beauty and perfection that goes with it.
The games and in particular SW KOTOR and TOR comes verry late in the timeline and they have the foundations from the old movies to step on and continue building up...
In the movies(especially IV,V,VI) the creators had limited time and technology to create by the best of their abilities the clothes for the still naked baby body of Star Wars(if i may express myself by that metaphor)
Later on we see improvement of effects, combat scenes, world enviorment, alien species in episodes I,II,III and VII(for the last one i remain without opinnion if it si improvement or else)
Bet there is so much you can tell and show for this 2-3 hours(per movie) about Star Wars Universe...
About the Games - well here you have the Absolute Freedom and Power to redesign the already known product into something much much better.
Especially Kotor1,2 with their long long hours of Role Play gameplay in which we are flooded with information about everything we never knew....
But back ONTOPICK:
In one of the comic books Darth Sidious used so powerfull force STORM that he(if memorry serves right) destroyed a starship into the atmosphere of Coruscant from some room in some Building planetwise...
Further more, take The Force Unleashed 1 and 2 and compare the Display of Overwhelming Power Starkiller is wielding both with the Force and by Lightsaber skill.
The story of The Force Unleashed game series goes like link between episode III and IV of the original movies and can be considered as modern times, long after SWTOR universe was put to rest into dusty and forgoten datacrons.
There are countless more examples to show that "modern" Jedi and Sith will have to say a thing or two to their Old Republic Colleagues...
About Master Yoda, in the movies he is already in his twilight years and still he was a something to not f*ck around with.
I wonder of what he was capable of in his prime...
On the other hand - Yes maybe some of the sith Lords and Jedi masters of old are undeniebly stronger than "new era" Jedi/Sith but we are speaking of thousands of years in between them - years in which The Force like the main energy source of life takes little off time to recharge then BOOM it goes back for a new Era of Galacic comflict tearing to pieces the very fabric of the universe...
Valkorion is no doubth one of the most formidable oponents we ever saw but like all beings of power almost overwhelming, he must have a one tiny weak spot which someone prepared enough will see and exploit leading to his underdoing....
And one more thing, what about the Rakatan Empire - they were Rulers of ALL the Force Surved for their ultimate weapon and shield, they left behind powerstations, temples and machines that even in the Highlight time of Old Republic with all its Sith Lords and Jedi Masters, are considered as something outstanding and mysterious.
Doesn't that mean that in their day of suprimacy, the Rakatan Empire was even stronger than Old Republic Empire and Republic combined togather....Yes i think that they were, BUT...
Where are they now? Like all things pasing trough the riever of time - they came, evolved, enslaved and ruled only to fall, scatter and sink into oblivion.
So back on the begining - it is not just you - there is significant difference between dispay of power wielded in both Old and New Republics - but we have to take under consideration the few points i made about how back in time lies the actual creation of New Empire and Republic(Rebbels) as we know them,
and how foreward in timeline lies the story of SWTOR when the technology used to create it is many many level higher(which opens dors, and gates that were closed and locked back in the day)
As an ending i will use my opening words:
Evolution, my sw friends - Evolution!