I completly disagree with you. In the first place the biggest pool (F2pool) is a pool with individual miners, so no centralization at all. Second, the hashrate is more or less evenly divided over at least 8-10 pools, no centralization there too. Pretty much the same as bitcoin.
And calculating the pool that support segwit and their current hashrate, we are at ~23%, as simple as that.
So, I don't understand why you say ltc is centralized, because it is absolutly not.