Buff towers but increase rewards for getting kills or other kinds of objectives.
A worry people have is that through buffing towers were gonna go through 50 minutes games every time so how about we take some agency away from destroying towers and put it more into kills or other things of the game.
So let's just imagine, towers go back to normal or are better, diving means you actually need to be a tank, late game squishies can't tank like 20 tower shots, towers eventually become a bit scary to tanks if they are able to tank over 20 tower shots late game, towers have more defense in general.
Give champions more gold for kills means that getting kills and playing to make plays around kills brings greater rewards. Get items sooner and get to take down towers better. Or we could make farming give more gold or dragons give gold along with the stats which puts some more pressure on getting all dragons even water or something. So if champions are able to get items faster perhaps we leave tower armor really low but increase the health of towers. Meaning those extra stats you get from items would help you take down towers faster.
So a problem we got is that games feel like they're decided by 10 minutes because the enemy got a small lead, got first tower gold and is taking down your squishy tower mid. By buffing towers they go from sand castles by 15 minutes to actual threats throughout the game. Would make games feel as lop-sided with a couple of kills though. For top laners this is a issue that comes up a lot. Just something to consider.
We still have Rift Herald/Earth Dragon and there's champions that have specific abilities to help take down towers like Tristana or Ziggs.