Certain req drop rates

So i was lookin through my reqs to sell most that i dont use, and i noticed how the ammount of variants of some weapons/vehicles really ruin the drop rates for other weapons. Phaetons for example, their drop rates are so low not because they’re legendary(i have plenty of other legendary vehicles and wpns) but because there are only 2 variants of it so ppl will more likely get 1 of the 20+ warthog variants then getting 1 of those 2 phaeton variants. Same with some weapons, i so many snipers(50+ unsc snipers, 75+ binary rifles etc) same with saws(100+), but only 1 sentinel beam…a sentinel beam is only a level 3 rare req yet i have more mythics then sentinels…why? Because there is only 1 sentinel beam variant unlike every other weapon and vehicles in the game, which really ruins the drop rate. They really need to increase the drop rate of reqs that have less variants(sentinel beams, phaetons, wasps, splinter/rocket/gaus/plasma turrets etc). Its as if they didn’t use their brains when designing the req system…smh