Nice name.
Anyway, I'm gonna vote no support on this. This would change end game UIM gameplay a decent amount so I'll get into it.
I own the bandos set, the armadyl set, void and lets pretend that i own ancestral as well. Imagine that I'm hunting drops from the corporeal beast, the chambers of xeric and the theatre of blood:
To do any of these activities its important that i have inventory space (I cant kill corporeal beast if i only have space for 2 food). Therefore I have to be really careful about what I have in my inventory. If i wanted to have the gear for 3 combat styles then this would take up a majority of my inventory space and therefore i wouldn't have enough room to carry the food needed to go to all 3 of the places i wanted to. Instead I might compromise by getting some sort of melee setup and some sort of range setup. This would allow me to do corporeal beast and raids 1 whilst still carrying about 15 food. Not optimal but do-able. If i now want to do the theatre of blood then i must suicide and set-up my inventory again.
If you're suggestion went through then i could simply keep all 3 combat styles of gear in my invent at all times and still have room for food. I wouldn't ever need to suicide to get gear out because it's all in my inventory. (would only need to suicide for skilling or something like that? idk)
In my opinion that would be too easy and therefore this suggestion would be too OP. IMO half the enjoyment of UIM is managing my invent. I'm also sure that some other ultimate ironmen would approve of your suggestion but I think it makes it too easy.
TL;DR I could carry gear for all 3 combat styles at all times meaning I could do any PvM activity without having to suicide to swap gear. IMO this is too easy.