Should be longer in the second half of the game.
I wouldn't mind if it was even a little more dynamic - like if you are actually doing something (like making trades with the bank or building roads or whatever) that it give you a bit more time, versus when you are doing "nothing" but thinking (as one can think between turns)
[maybe it does this, I don't know... ]
@Wootah Are you referring to an expansion like cities and knights or is this a comment on the base game?
When you have 10 or more cards it takes time to play them. Also a visible counter might help.