It would be convenient for solo and pub players, but since this map is so heavy in team play, it would be more of an annoyance to most, since a lot of strategies involve pooling team money towards buying complete items, instead of having each player work individually to buy their stuff.And it's a lot of work, since he'd have to edit each recipe trigger individually to get that done.
I don't see why you think it would be an annoyance or not-beneficial for experienced players as well. I never said to get rid of the traditional way of buying recipe items. I only suggested to add in the ability to buy everything altogether at once when you click on the recipe and have the required amount of gold. It might be a bit complicated to explain but if you check out the battletanks map then you will understand what I mean.
I'd love it if its possible to e.g. fullbuy an item if you shift click or whatever, but i dont think thats doable in wc3.
Do check out the map in the link provided. It is completely possible and has been done before. Better yet, the creators of the map that has htis function implemented provided and non-locked version for people to mess around with so we can use that map to see how the function would work.
I don't know enough about map editor to suggest how much work it is but I do think that it is quite a bit of work. He can see how it works by looking at the unlocked version of the map I provided a link to though. If he wants of course, just a suggestion.
That being said the issue remains that it's a pretty crazy amount of work to implement, and while quality of life additions are pretty great to have, I don't expect Inmortal to spend that kind of effort on it.