In 1v2, the solo is at a complete disadvantage; solo doesn't get to take as much advantage of meter than the 2-man team can, and their damage isn't that much smaller. I mean it is, but when DHCs come into play, it's hardly a question of whether or not you can do higher damage but rather how well you know your characters enough to keep the counter going and the health down. The solo's gonna have to rely on health and damage advantage alone to prevail over a good team, because whatever it can do will always fall shorter by comparison.
1v3, however, is a different story: it's almost equal. The 3-man team is generally weak and you had just better have good enough knowledge of your entire team and a great set of assists. The solo's health will take so long to whittle away that it can be an afterthought, with the best ways to take it down being a lot of patience, exploiting character utility, or both. But a simple BnB from a solo is enough to take down most, if not all the health of a 3-man member. (depends on meter)
Unless you're Squigly or something. I mean it's possible but the effort of playing her is better spent on teams.
Generally the advantage goes to teams, but IMO solo is pretty damn fun. One could argue you could simply be playing MSH instead.
Yes. Indeed you can.
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But MSH doesn't have best wheel.