Why should they be banned? I think there are two options, suck it up and race against people using 4wd as 2wd, or, if you think the advantage is so great, buy one/run one yourself. I personally think a lot of this is down to rumour mill and kidology, 8/10 cars at a national A final were these cars, how many of those would have been in the A final anyhow? Were there any huge leaps from people who would normally be D/E/F/G... final finishers?
I personally don't think there is anything to ban, if there is some sort of gyroscope handling package going on here (i remain sceptical) then it should be developed, not banned.
Ban innovation, ban progress, ban people beating me!