The Wirbl THIS tour alone has over 17000 kills. That's more than the La7. That's more than the spit16. That's second only to the P-51 when compared to aircraft.
Pretending it's not effective so you can coddle the whiney GV players isn't the answer.
P.S. R105 the human eye is infinitely better at seeing than this game can display on a pixellated LCD. It's not accurate to say the human eye is worse than this game. It is in fact better in many ways, and they have all been discussed, proven with math and with actual experience from real-world pilots. 20/20 vision would have no problems seeing a giant 20-to-40ton tank sitting in a field. In this game we have a much harder time.
EDIT: Funny thing.. you can look up the stats, you know? The vast majority of those 17000+ kills are all planes. Naturally this thing isn't so effective against tanks. However, if you check the kills, this tour alone it has died more from combined P-47 action than from lancasters. It's died infinitely more from other GVs than it has from even IL2s or A20Gs... GVs are the vast majority of Wirb killers, and yet they keep asking for more and more unjustified concessions against planes.