You are definitely right about the fact that the game is much different at 2/5 than it is at 1/2, but there are a couple things to consider.
#1) Not all players are playing 2/5 because they have money. You will run into people that are playing 2/5 for the same reason as you, they take poker seriously and can now move up in limits.
#2) I don't think the "You have to tighten up to move up" statement is true. I deal at a casino in Niagara Falls, NY and we run 1/2 and 2/5 everyday. What I see at the 2/5 table is players that are very aware of the tight players. You will not get paid off if you are only playing premium hands. Now the 2/5 game I deal is usually filled with the same 4-5 guys so they all know each other, but just letting you know what I see at work.
#3) Much like how the floor and dealers know you, once you play 2/5 for a while, the players will get to know you (more than the 1/2 would). Obviously there are less players playing 2/5 at the casinos
than 1/2 right now, so if you play 2/5 regularly, you need to prepare to mix your game up.
#4) 2/5 is way more profitable and not because of the bigger pots! It's because the rake is the same as 1/2. In 1/2 we take $3 on the flop and $1 at $40. In 2/5 we take $3 on the flop and $1 at $40. So at a 1/2 game most pots get 2bb taken out where as at 2/5 only .80 of a bb get raked out.
Welcome to 2/5 and congrats on moving up!