Alien and alien queen share the same abilities(bleeding on hit,tangle on rage etc) but (not considering the model) they have some differences:
1)Alien is slow but alien queen is fast.
2)Alien queen's stun range is very short but alien's stun range is short
Since alien and alien queen's stun range is extremely short they can't deal with sentry nests(sometimes alien queen has more chances because she is faster) and they can't even try to get them using super jump because both alien and alien queen have no wieightdown.
Also the the stun radius is minimal but the speed difference is easily noticeable making alien queen a sort of straight upgrade of alien queen

Wrong, Alien has bigger stun radius then Alien Queen.

Edited
Never seen alien queen having problem with sentries so i tought she had a longer stun radius than alien,but the problem is actually their speed.
My idea is to give weightdown to both of them and amplify
the stun radius of alien since the speed difference make alien queen stronge than alien.