I certainly agree with your comments regarding long term scalability- growing pains of ethereum if you will, now the great token hype of the last years seems to have tapered down (recent dair report makes sobering reading) it has to start offering something more tangible and cohesive than an easy liquidity vehicle for dubious whitepapers and teams of advisors to raise hundreds of millions for 5% stakes in proposed innovations like prediction markets armed with nothing more than a flashy site and a roadmap.
For now ERC standard is still entrenched as a dominant liqudity pair and has a certain amount of incumbency but I think there's plenty of room for challengers in the coming years; with stellar being just one of the 'competitors' on some overlapping verticals
By the way, you said Bitcoin is useless for custom tokens. I disagree, The CounterParty protocol has existed for almost 5 years as a meta-layer on top of the Bitcoin blockchain proper and works well to this day with more than a million yes relayed. (Not that you ever hear anyone mentioning it)
Not only was it the platform that defined the early token landscape It also launched the first decentralized exhange-- without ever raising a single cent of funding! --It was the main source of inspiration for early incarnations of ethereum (which was originally due to be built on bitcoin, then primecoin)
Counterparty enables fairly intuitive token issuance, distribution and trustless p2p trading with the protocol escrowing native tokens; (issuance can be done with only vanilla BTC, no sub token or gas fee for numeric assets) and much like Stellar the platform offers certain hard coded VM functions embedded within for smart contracts that go beyond Bitcoins script capabilities (CounterParty ported the EVM in it's entirety in 2014 but decided not to implement it on mainnet due to security concerns, this was pre theDAO and later debacles). It's natively interoperable with Bitcoin (BIP39, multisig, LN, segwit etc) and counterparty transactions are present in roughly 65% of Bitcoin transactions since it's launch.
It does seems to get universally glossed over in favour of more monied, much more hyped alternatives, I'm not even sure if many developers even in the blockchain space are aware of it.
Back to stellar though, StellarX seems great-- I am wholeheartedly supportive of anything than challenges these incumbent centralized exchanges business model of shaking down big ico's for listing fees, for starters. Also appreciative of their smart contract architectural design choices for leaner, minimal and more performant use cases where scalability is paramount and perhaps the perception of the lack of total decentralization vs "just" distributed consensus isn't a deal breaker.
Actually more keen on stellars proposal at the moment than ripples codius, currently evaluating a single contract across the board for comparison.