No, not if you’re raiding, eventing, mapping where the opposition is of different speeds. At least you get some time to play the board before they go off.
Traditionally, S1, slow heroes were slow to offset the high damage factor.
By having everyone on very fast that high damage factor now gets the advantage of vfast as well.
Playing Mono also actually allows one to take full advantage of elemental links, some families are also the same colour.
Putting everything to vf, imo, totally favours the defender, they’re going off regardless, bad start or unwanted combo and you’re dead. And it rather negates the fun of elemental and family links.
I have a very good Mono Red team where the specials and elemental links work really well together in all aspects of game except Rush where it’s all down to opening board and first 3 moves.
Btw, are you kilted? I’m Scottish, in Edinburgh.