If the game is TB that is bad enough that if it also had timed or in other ways constraining conditions on how you engage in combat it would be the death knell for my interest in the game. Honestly, none of the above sound fun at all. They would make combat all the more a tedious chore.
I'm wary of this kind of feature too. Back when I was playing Valkyria Chronicles on PC, I played every single mission for an S rank, and refused to move on until I got it. I played until just before the final mission and then just stopped, and never returned to it. I only meant to "take a quick break" before the last mission, and then just never found the inclination to actually do it. I guess I got kinda burned out at the end there, without actually realizing it, even though I did enjoy my playthrough, more or less. Was a huge pain to get S for some missions, and it didn't even feel that good when I managed to get it.
Exact same reason why I stopped playing Splinter Cell: Blacklist. I got pretty far in the game, and after one certain mission, I thought I did really, really well, and still didn't quite manage to get the highest rank. I felt kinda discouraged, and realized you'd have to pretty much speed run and pull off crazy plays throughout the whole mission to get the highest rank.
Someone could say, then just don't pay attention to it, just play how you want and enjoy the game. Yeah well that is easy for someone else to say. I like taking my time exploring the environment, experimenting with things, creating memorable moments, so the "achievement for fast completion" thing really turns me off.
