It depends on level design but for most levels that's quite true and it's why CTF tends to work better. It's also easier to make a good CTF level for that reason: the layout is grounded on two points, the bases. It also helps that CTF has 3 hearts instead of 5.

You're a bit wrong on the subject of CTF duels where you said if you stray too far from the base you can't score. This certainly applies to larger games, but in a duel you will score as long as you are reasonably fast and the spawn points are sane. Generally the blue spawn should be as far as possible from the red base, and vice versa. If not, it's probably a bad level for CTF duels.