I'm leaning a bit towards removing Team preview as it'll really allow certain Pokemon to shine and it really involves more skill. Now those newbies must be careful not to mindlessly send out that Banded Terrakion or that Scarfed Latios. Team Preview will force players to play conservatively, predict and ultimately plan a victory plan before the opponent does.
I completely disagree in just about every way. Gen 5 in its current state would be unplayable without it. The only reason Gen 5 is this lenient (and balanced) with tiers is because you can see a threat in team preview and know which Pokemon you need to keep safe. I would bet real money that Landorus, Terrakion, Keldeo, Wobbuffet, Latias, AND Latios would be banned if team preview didn't exist.
In Gen 4, it was so common to have a Pokemon fall only to find out that it was the only Pokemon that stops your opponent's not-yet-revealed late-game sweeper. For example, if you let your Jirachi faint because you didn't want anything else to take a heavy hit, oh look! Calm Mind Latias was their last Pokemon; what a shame. Ferrothorn faints; oh look! ...Calm Mind Latias again! Tyranitar faints and oh lookie here; another Latias. Oh hey, you KO'd my Ninetales on-switch with your Hydro Pump; it would be a real shame if I had a Wobbuffet in my back pocket. If you play this game any decent amount, you can imagine what Sheer Force Landorus could do late-game without Team Preview.
Pokemon was one of the last multiplayer RPGs to give you at least some information about your opponent. Some sort of team preview is absolutely standard in any multiplayer RPG. Some might call Pokemon charming for not doing that for so long, but I call it entirely out-dated especially for an RPG with over 600 characters and even if only half of them are fully-evolved, that is still a ludicrous amount of characters to have no idea which 6 your opponent has.
To be entirely honest, I think item sprites should (and most likely will) be shown in X & Y's team preview instead of that little box icon that just states the Pokemon has an item. Not having items show up in the party menu is so archaic that the only excuse for it is laziness. Gen 2 and even Gen 3 I can understand not having tiny item sprites due to the size of the screen but this should have been in Gen 4. Having to go into the status menu to see which item my Pokemon has is a waste of time the player's time that has no business even existing. But from a competitive standpoint, with team preview as it is now, there still isn't enough information to form a
reliable battle strategy. Again, it's an RPG; strategy
is the game. We should be able to have a good idea of what our opponent's sets are and be able to plan accordingly. If one of your Pokemon gets taken out, very rarely should it ever be your opponent's fault. You knew the risk and you took it anyway so it should be your fault. But right now, each Pokemon has 3 good sets they can run, sometimes with completely different checks and counters, and you have to stick your neck out just to figure out which one it is and if you guess wrong, you can end up crippled the entire match. No one should have to employ "Plan C" every single battle, win or lose.
But I'm gonna stop here cause I think I made my point and I'm just going way off into rant mode.