Highlander might be better without sniper, but it wouldn’t matter if it was true. One of the biggest appeals of highlander is that you can play any class you’d like full time. If we remove sniper based off balance/how they affect the flow of the game, then I could potentially see an argument for removing other classes from HL as well. At that point it’s not even HL anymore. Just play 6s if you don’t want to deal with sniper.
Also, I understand why most demo players don’t like playing against decent pick classes, but I honestly don’t mind it at all. Decent snipers punish bad players who are impatient/don’t understand the concept of sniper sight lines. All of your weapons arch on demo as well, you theoretically don’t even have to peak a sight line to apply damage if you just knew most of the spam angles. Obviously that’s just theoretical, but my point is that there are plenty workarounds to playing against a good sniper.