Now don't get me wrong, this is going to be a monumental battle no matter the outcome, and certainly the villains start the fight with a notable power advantage. But the "coaches" offer various benefits that nobody has seemed to consider when giving a response. Here's my take on the matter:
Thor, Silver Surfer, and especially the Hulk are renown for holding back via mental restraints. Thor virtually always withholds his full power when on Earth. This is a well-established facet of his mythos. Surrounded by mortals most of the time, Thor has grown subliminally accustomed to keeping himself in check. So, too, with the Silver Surfer --whose restraints are tied to his guilt over helping Galactus murder so many billions of beings across the cosmos. Then there's the Hulk, who has Banner constantly holding him back from within and is emotionally bound to protecting the innocents around him from his power.
Those who don't see the role Professor X could play in "enhancing" those three to gain an edge in pure power, seem to be missing a big piece of this puzzle.
The setup to the battle included this description:
'TEAM HEROES is coached by Professor Xavier, who uses his psychic mastery to link the minds of his team together, enhancing their awareness, tapping their potential, even working mentally with or through them on the battlefield.'
Starting with the obvious, if Professor X worked with the Hulk to unleash WorldBreaker (who is provably leagues beyond Mangog, for example, in raw might) then the power dynamics of this conflict shift dramatically. The Hulk's potential, which is infinite, is typically tied circumstantially to his ability to access emotion. Xavier is a game-changer on that front. With the Hulk's agreement, ala with Jean Grey vs. Onslaught, he could fuel the Jade Giant to heights of power that would otherwise require insane levels of motivation to accomplish. "Coach" X gives TEAM HEROES a nuclear option with the Hulk that affords them raw power the villains simply cannot innately match.
A similar argument could be made for the Silver Surfer, whose power also has no ostensible limit, but has psychological inhibitions that prevent him from fully unleashing. Xavier, again, is potentially a deus ex machina in this scenario; or at least presents the possibility of turning one (or all) of the big-3 powerhouses (Thor, Surfer, Hulk) into exactly that for his team.
Add to the mix Sorcerer Supreme Strange --who with all his talismans together once briefly matched power-vs-power against Adam Warlock with
the Infinity Gauntlet:
"... an outpouring of power against power which would lay waste many a world, if any were near at hand. The result is a momentary equilibrium of power."
--and I think many here are underestimating the significant threat Doctor Strange alone portends for TEAM VILLAINS. On his best day & pulling all his tricks, it's not inconceivable Strange could contend with the bad guys here on his own. When you consider that he'd be psychically linked and working synergistically with Professor X-enhanced versions of Thor, the Surfer, and Hulk (alongside the Spirit of Vengeance) and I believe the heroes have access to more raw power here than anyone thus far has given them credit for.
Versatility and matchups could also play key roles in shifting the tide of battle. For instance, if the Surfer engaged Ultron first the villains could swiftly lose one of their mightiest members, as Norrin's ability to manipulate matter and all forms of radiant energy would likely allow him to make short work of the robot --by either sucking all the nuclear energy out of him and/or turning his armor to rose petals. Instantly, the villains are at a numbers disadvantage and might have a completely unleashed Thor & Surfer double-teaming one of their other fighters.
Now of course, Doctor Doom presents a wildcard all his own and could potentially counter Professor X's presence in other ways. But those who dismiss the heroes based on how the stock power-levels of these two groups match up with one another, in my opinion, are offering only a veneer examination of how these teams stack up.
WorldBreaker Hulk and an all-out Sorcerer Supreme might be too much for these villains by themselves. Certainly, the bad guys could figure out ways to come out on top --with their raw might and unmatchable genius & experience level-- but it would hardly be the one-sided walk in the park everyone, so far, has contended.
First Knight, Church of Hulk