From the what I've played so far, I can already tell you that both assassins and bruisers dominate here. They get bonus points if they're mobile. If I had to rate the champion types from most useful to least it would go something like this...
God tier
Assassins, Juggernauts (They both have high objective control and are very self-sufficient. Cheap builds and a threat from start to finish.)
High tier
Supports, Bruisers, Fighters (Same reasons as above, but doesn't take as much effort to keep most of them in check.)
Mid tier
Mages, Tanks (Very dependent on which champion/team comp you're playing, some are vastly more useful than others.)
Low tier
Marksmen (ADCs) _(Too item dependent and most of them are very reliant on their team/coordination to succeed. They can work, but in general it's going to be an uphill battle.)
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