It’s the ‘stable door’ syndrome. RB was clearly never intended to be used with single-shot weapons - it was originally touted as a special ability with Deceptors, so that you could do the Arnie thing with a gatling-gun - but they didn’t think to limit it in the orginal build, so when some enterprising player discovered that a Sniper/Heavy could use it with a Sniper Rifle, everyone jumped on the bandwagon.
A 15-shot RB with any Sniper Rifle in the game effectively killed any target stone dead. So they nerfed it to 5 shots - coincidentally as many as a full mag for a Deceptor 
- but didn’t completely shut it down; and now people expect to be able to RB with Sniper Rifles.
But like I say, I don’t want to deny you that pleasure. Personally, I think it’s an abomination, but if they can give us both what we want in a Second Wave, that’s clearly the most popular solution.