I have no problem with that, and yet I don't think it's necessary. Let me explain that.

I have 'kinda sorta' followed a Matilda I -> Valentine Echidna -> Churchill Vortex idea with tiny numbers as 'funnies' for very specialised functions. It's come from having the Australians using a 25pdr Sentinel/Matilda I combo, and matilda I are like hen's teeth. So an applique armoured version of Valentine with the 2pdr replaced by a .50 cal water cooled Vickers MG with a 'troop' of 1 Sentinel and 2 'Valentine Echidna' as a dedicated Japanese field fortification busting team has resulted. Depot conversions of Canadian-built valentines to this configuration would be done at Chullora railway workshops in Sydney, and there might be what, 50-60 during the course of the whole war?

Providing a similar 'heavily armed with automatic weapons escort tank' for Arras (ToG) seemed like a good idea, and A22 Churchill I is perfect (when refurbished!) as again only small numbers are needed - perhaps a couple of hundred if that. After all, it's really a 'funny'.

Now, to mobile AA and 20mm Crusader Mk III. We have a metric crapload of otherwise useless Crusader's building up in APOD. many we are going to convert to a primitive APC for OVERLORD.

But I think a lot get an AA makeover.