you guys may want to check out the Dex built off of TN called Polarity.
Im pretty sure that everything you guys are hoping for has all ready been taken care of.
The high gas issue is that currently, the majority of DEXs use the Ethereum network. It is the auction mechanism and confirmation time that make people want faster transactions.
Currently, Justswap is a DEX based on the TRON platform and has a lower transaction cost. It resembles a copy of UNISWAP and is supported by TRON.
I believe there will be a lot of new blockchains that generate DEX and a much lower cost. Of course, those DEXs will appear in the future.