I'm not sure where the confusion lies, but the warrior units can fire at anything with a toughness, our poisoned shots work especially well against
MC(since their toughness means nothing to us

), but also great at flooding anything with a toughness with mass of shots.
I assume you mean 3 raiders and razorwing for the 6
DLs. First of all, you have to roll for
BS before penetration rolls, so for simplicity sake, you're looking at 4
DL hits, against AV10, you may be able to rely on getting a penetration, but as the
AV goes up, the chance goes down... Which lead to the next problem, our units are all extremely fragile, you may very well not get a 2nd turn to fire those raider's
DL as it honestly wouldn't take long for them to be shot down. Lastly, while razorwing can also fire those templates on the vehicles, most would consider that a waste, razorwing is better at dealing with infantry blobs with those templates... Obviously, if your opponent is to be so kind to have all the vehicles deployed in a tight circle, then you should brofist him then proceed to put a template down on his parking lot, but I realllly can't see that happening regularly. So, in short, 6
DLs aren't very reliable still.
As for other effective assault units, I'll just briefly go over them all.
Beastmasters, very cheap units that have a lot of wounds, 4++, lots of rending attacks, and go especially well with Baron.
Hellions, quite expensive to be field effectively, also requires Baron to be run well(so not great if you also want beastmasters), but they're our only assault unit that is also very good at shooting.
Wracks,
FNP nerf did hit them slightly, though not quite as bad as it is for the wyches still, can bring 2 liquifier guns to soften enemies up, and can do a mass of poisoned attacks in
CC. Also relatively cheap.
Grotesques, expensive, but our toughest
HQ escort, can brute force a lot of enemy units with them.
Harlequins, shadowseer got buffed, so they become kinda usable this edition(very usable if you use with eldar, see: harliestar), also can do a mass of rending attacks.
And of course, there is the incubi that you're using already.