Sometimes you need much time to think about a move, since you look what the opponent will do in the next round, 2nd next round etc. Additionally to that you may want to calculate some dmg output of your Pokémon in a calculator, take account of Iv's as well. All that need time.
Thats of course not every round the case but when you play a team you are not experienced with or when you don't have the most calculation factors in your mind, which probably applies for the most of us, you may need this time and maybe sometimes even more.
The best system would be, in my opinion, like in showdown. However, thats not workable at the moment I think.
In general I think we should not shorten the timer as we have with the new stalling rule a rule that would punish possible, intended, time stall. As well I don't see many users using the full time always, but sometimes in match changing situations. I think its good how it is for now,