"In order to promote activity in the 3v3 bracket and due to naturally low rating teams occupying top ten slots, players will only qualify for Gladiator titles if they're above 2 000 rating."

3v3 needs a lot of help, so this is a welcomed change. But you're gonna need a bit more to make people play 3's. From personal experience, it's either one team you're facing every game or (usually this is the case) no teams at all and you're stuck in queue for 30 minutes until you decide to give up.

I suggest rewarding players more points for 3's games or making WF gear obtainable with a bit less 3v3 rating (ex. make the WF head obtainable with 1700 in 3's instead of strictly 1950 in 2's). Some little changes that won't affect the PvP system too much, but might revive 3v3.

Even a pet vendor might work (I mean, you're giving out pets for Cow Darts, might as well put it as a 3v3 reward).