After I filed my response denying all allegations, they blinked and we made a small change to the description of the trademark. (Something that I had offered them from the beginning).
From my perspective the worst that could happen is I would get to the point where I needed a lawyer (actual discovery) and could determine if it was necessary to continue.
Filing an answer to an opposition is not difficult and a little online searching goes a long way to help you avoid making mistakes answering the opposition suit.
They may seem to have unlimited resources, but a legal dept doesn't actually have a bottomless budget, and it has to demonstrate ROI to the CFO's office.
Many attorneys you might consult won't realize this, because they can't conceive of a scenario where you don't need maximal legal representation. When your only tool is a hammer, every problem looks like... :-)
There already is one, it's called hourly billing. You come up with a reasonable plan, and you decide when to call it quits later if the bill gets too high.
I think that's incredibly unlikely, (in the US legal system there isn't a lot of cost shifting for trademark suits) but if you assume that the person responding to the lawsuit doesn't know what they're doing, then I can't rule it out.
Edit: The downside is that it would also prevent poor plaintiffs from suing richer ones. But that is already generally the case. It's probably best to judge on a case by case basis.
Alternatively, you could cap the amount the looser pays to what they themselves payed, devising some sort of scheme to prevent exploits around lawyer-on-retainer/permanently-hired-lawyer on a large-entity's side.
For example, in breue's case he had enough money for lawyers, but pretend it was the same scenario only breue was an 18yo still living with his parents (who are not wealthy theoretically)
Does the judge just blindly believe everything Twitter says since they have lawyers?