I have to agree with @Calico45.
In a "perfect world" what you suggested would be wonderful and amazing! I would be thrilled with them updating the existing packs with a few more game play items.
But we're talking about EA here. I see 2 issues with this suggestion (thinking from how we know EA thinks)
- Updating existing packs cost time, money, and resources (pulling people off of working on new packs to work on stuff for existing packs) = absolutely no monetary benefit
- Not making kits = losing out on potential monetary benefit.
Now, if we're talking making the kits actually be a cohesive and non-random stuff that will actually work well with existing packs, then I'm all for that. I personally would rather have kits be something that "enhances and enriches" the game play aspect of existing packs.
And yes, I know people would go all ballistic about how this or that should have been in this pack or that pack, which I'm not denying it should!
But to me, if I had to choose the lesser of 2 evils out of A or B:
A: Kits are just random hodge-podge things that don't really fit existing packs functions, themes, or both
B: Kits add on to existing packs by introducing new gameplay elements that work cohesively with existing packs on both themes and functions
I will chose B every time!