Thoughts on possible beneficial changes

Take this how you will, just a suggestion, but currently around 70% of the League roster is not viable in 99% of games, in my own experience. I think this can be fixed by streamlining stats and ability scaling, and just having items make up for it, still keeping ability effects. You'd see a lot more variety, a lot more viability for champs currently not, and overall, I think it would make the game far more enjoyable for everyone. Not to mention that I think it would make cheaters that much more obvious by making it well known how much damage can be dealt on average.

What I mean is like this:

Mages are mainly AP focused, so have them start with low AD, low-mid HP, but higher mana and a minor amount of AP. From there, items make the rest of the build.

Marksman champions need more AD/Attack speed, lower HP, and medium mana, no AP.

Assassins get moderate AD, attack speed, and health, but low mana.

Tanks get high HP and defenses, but comparatively lower AD and mana.

This way you have a good base to work with new and old champions alike, basing their stats off the categories they fit into, and having all abilities scale about the same.

Some champions like Veigar might need additional scale tuning to work, as Veigar in particular scales infinitely, and thus in this regard might end up overpowered if his AP scaling isn't tuned down a little compared to others. However, as for the rest, it makes them viable without having to worry about overtuning or undertuning so much, because it would rely more on items than the champions themselves, as opposed to some champions scaling far beyond others, and some not scaling anywhere near as much as others, as it is now.

As I said, these are just my ideas. Feel free to get back to me or not, it's up to you. Just trying to think of how the game could possibly keep improving and adding more and more champions - as you do - while still keeping everyone at least viable.

PS: I heard Riot wasn't going to work on Ryze, Azir, and Kalista any more, but that's why this would be decent to do, because as it stands, if they reverted Ryze after doing that to what he was like pre-rework, he would be just fine, as opposed to entirely not viable at all as he is now, or overly-oppressive as he originally was, and the other two would be back in the meta.

Any thoughts that might improve on this idea, or maybe thoughts against it?