Ok I love to bash the balance team as much as the next person (Hell I think I'm on Maple Nectar's bad list from it)
But they are NOT being paid to do nothing, Balancing a game this large is a nightmare, sure its is their fault for their old philosophy of "A new champ every month" bloating the roster and making a mess but hey ho they made their bed and such.
So with the whole matches lasting 10-15 minuets, sure some matches are decided that quick (Looking at you Placement matchmaking...) but the issue there is despite the whole "muh pro play" stuff a shorter game length means those with less time can enjoy more games, this might come as a shock to you but some people have obligations outside of this game, Some people don't want 45 min long matches.
Why make Elder and barron stronger? See again game length.
Why is damage creep going out of control. Game length
Zeal Items. Ok this one baffles me, increasing it by 100-200 gold is only 1 to 2 minions waves worth of CS, a 30 second delay. unless you say increase it by 50% of the cost (In which case you gut the item) how would that solve the zeal problem? Want to fix it? lower its stats not up its costs.
Also the balance team would be getting 5 figures, 6 figures is reserved for very high up roles or senior programmers