I dislike both the KO'd legendary respawn and the unlimited use of TMs. One major part of preparing a team depended on the moveset you would use for each Pokemon. Many rare moves learnable by TMs were considered valuable, and as such, played a pivotal role in creating a team. Since those rare moves can now be used indefinitely, trainers can just assign any Pokemon the move without having to care about losing it. Now, certain moves will be abused much more and most of the moves in the game will be at your disposal. This, in my opinion, greatly degrades the competitive nature that Pokemon is known for.
As for KO'd legendaries respawning, I believe that having such a feature removes the excitement and suspense of battling a legendary Pokemon in the first place. Since I know I will be able to have another attempt at catching the Pokemon regardless of my reckless actions, I won't be nearly as careful when trying to catch one.
I'm against both ideas, and I feel that Nintendo and/or GameFreak is making Pokemon too "casual-friendly."