1. I think ETH has a future if it can win the race of fixing its issues before another project overtakes it in adoption. Its first-mover advantage has given it a massive head start, but the competitors behind it are moving much faster and closing the gap. If ETH can pick up its pace before they catch up, it has a future, if it can't, then it does not. I find it difficult to speculate whether it can, but I'd put its odds at near 50:50.

2. I want to see PoW beaten as the future of consensus by either PoS, DAG, or FBA. I would be sad if, in a decade, PoW is still the dominant consensus mechanism. So far, no major failings have been exposed/exploited in the other mechanisms, which is encouraging. There is already plenty of money to be made in attacking them, but no successful attacks have been carried out, to my knowledge (maybe on IOTA, but I don't think highly of them). Based on that, yes, PoS has a good shot at being the future.

3. My answer to this applies both to Casper and Plasma. I've spent some time on the Ethereum R&D wiki pages, and even the more simple articles there, like the PoS FAQ or the Sharding FAQ, are already quite technically complex, even before considering their respective published papers. I like to think of myself as an intelligent person; I have two Computer Science degrees; I'm an experienced software developer; people pay me up to $125 per hour for my expertise; but I still struggle with fully understanding the finer points of their arguments. If I spent a few days studying, then I'd probably understand it fully, but I'd still lack the domain knowledge required to assess it within the broader context, which takes many months to obtain.

   Most of us don't have the expertise to make judgements on things like this, nor the time to gain that expertise. There are people smarter than us arguing one thing, and equally smart ones arguing against them (e.g. Paul Sztorc vs. Vitalik). All we can do is more or less blindly trust one side or another. We usually do this by looking at the vision they're promoting, or the results they've delivered so far. My main reason for trusting Vitalik is that he's delivered a product with massive uptake and mindshare that's been battle-tested and survived for years. If he says that Casper and Plasma will fix its shortcomings, that's good enough for me. I don't have time for the months of study needed to verify his claims. When someone else delivers a better product, which then survives heavy loads and attacks, I will switch my allegiance.

Basically, I want a better smart contracts platform in the future. It doesn't matter if it's Ethereum or something else, it just needs to be the better one. But my definition of a better one includes having undergone significant adoption and survived the heavy loads and attacks that came as a result of that. At this point in time I'm choosing not to speculate on another platform passing that test, and speculating that Ethereum will fix its issues in a timely manner instead.

P.S. I don't know your background, but before you accuse me of being too stupid to understand the tech, consider the Dunning-Kruger effect. As someone who's been in the field for a while, I am acutely aware of how much there is I don't know, and how much context and theory can be behind even seemingly simple statements in those R&D papers.