It really isn't any more messy than dorito powder or salsa.
Not fond of either of those options either, for the obvious reasons.
Hummus is a healthier alternative to salsa, and its less prone to getting watery in the bowl like salsa. Watery dips are to be avoided at all costs.
Bagel chips are preferable from a health food perspective to doritos and potatos chips, though really the whole chip concept is probably bad to begin with. Fortunately, I don't like chips much so they don't tempt me.
Popcorn is a good munchy, and as long as you don't heavily salt or oil it, its both a game friendly and healthy snack.
I've seen recommendations for sushi rolls, which would work well, but making enough veggie 'sushi' to feed a gaming army would take alot of time and effort and ordering them out would be prohibitively expensive.
Unsalted almonds are my current snack of choice, gaming or otherwise. More filling than sugary snacks - the protein and fat stays with you in a way that carbs don't - and relatively healthy. A little goes a long way though in terms of calories.
Grapes have a handy natural packaging (as the grape growers of America are fond of pointing out). Now that you can get good seedless grapes (I imagine only the older generation here can remember when you couldn't) they seem like an excellent choice. Too much reliance on fruit though would be bad, both from the calorie perspective and from the perspective of post gaming digestion.
I think the real problem here, and the real reason you see bags of chips, raw vegetables and the usual snacks is that for the most part people don't enjoy putting a lot of time into prepping snack food - whether for gaming or otherwise. I'm sure that there are some amazing snacks out there, some of them even healthy, but you'd probably have to spend half a day cooking to make them good enough to remove all temptation for the easy stuff.