I dunno about a separate button, but I'm not gonna lie that 45+ card decks are the best.
I mean, take a look at this beauty.
5c5 5c5 5c5 5c5 5c5 5c6 5c6 5c6 5c7 5c7 5c7 5c7 5c7 5lk 5lk 5oi 5oi 5oi 5oi 5oi 5oi 5oj 5oj 5oj 5oj 5oj 5oj 5ol 5ol 5pu 5pu 5pu 5pu 5pu 5pu 5pu 5pu 5pu 5pu 5pu 5pu 5pu 5pu 5pu 5pu
Team Air used it this war, for one under-publicised game, and it was awesome. I was inspired. I got this deck out, replaced two to three of the cards for upgraded copies, bought myself a few more of the air pendulums, and PvP2'd.
And yeah, the back and forth. With 45 cards, the games are slower, and it's a bit more planned and stragetic.
Essentially, it's like a good, proper rally of tennis, rather than a serve (Ace!) or serve and miss, or direct reply winning.
The thing is, I dunno about an extra button. It kinda takes some of the surprise and fun out of deck out stalls and ect. And it looks a bit weird IMO. (However, I am in complete agreement that less different cards/more cards is the way to go for a funner game)