i dont see the need for a limit at all in Pug games, you cant co ordinate with your team so you have to take one of everything or risk missing critical elements and then you may have dead weight from quests forcing you to take mercs i wont play.
so healer, killer, obj spec and then quest guy. let alone if i want to take a long a new guy to try out.
but i also think its too many for competitive , in a full premade scenario i think 2 would be better and 3 offers too much flexibility.
I feel like 3 is enough for objective matches and c4 stopwatch matches, but it’s not enough for EV stopwatch matches where objective specialists have no function on defense and you can’t do significant damage to the EV without an explosives specialist.
Different stages of each map favor different mercs. If you could take any merc at any time, each stage of a map would only see the meta best mercs for that particular part and the game would get stale faster.
That’s why the explosive specialist should be your second pick.
The third one… Either a Medic or a Sapper.
As OP started the listing, mercs are category orientated like so; barely-licensed drug specialists, DIY engineers, psychologically unstable all-about-killers, peek-a-boo pervert recons and ammo-men, -women & -weirdos. So having an ability to choose 3 mercs out of 5 different categories looks like teamplay attempting developement decision which isn’t gonna change as far as I see. Even when new mercs are introduced, categories stay same. Time will tell though.
Liking how it’s now, since as someone already said, it also forces player to play differently with the merc not so efficent for the occurring situation instead of just falling down to picking the best around.