possible in game gold sink: Additional Overpriced upgrades for boots.
aside from mejai's soulstealer and sword of the occult, the cheapest complete items in game start at 2100.
t2 boots range from 800-1200, and 475 for upgrade with a max cost of 1675g, not much value for an entire item slot.
many games end up going for a long time with players sitting on full builds and excess amounts of gold until the game ends.
I propose additional upgrades to boots e.g.
for 750 additional gold your boots gain 10 movement speed, with the next 10 movement speed costing 1500 gold, then 2250g up to a maximum of 50 additional move speed for a total cost of 11225g(I doubt anyone will get to that point without a custom game.)
Its most likely that players will upgrade once or twice, and rarely a third time.
I mean when there is nothing else to spend your hard earned gold on, why not sink it on something overpriced with minumal value? where else would the gold go?
at that point in game the average speed of a team is around 450, 20-30 isn't game changing, and it was gold earned by doing good all game that person deserves something for it.
plus it gives boots better late game scaling