Wow that's lovely principia!
I agree with all you say - about over-enthusiasm, having lots to discover (but not so much time and space to try all you'd like..), and having to find my balance between permanent / annual garden features.
I think I'll have cycles of 'oh no, my plants die I'll quit' and 'Ah never mind I'll try something different next time'
Just like you I've planned which crops I'd like to try next year (it'll be hard to wait until the next spring but I'm learning patience!).
This year I've grown Gardener's Delight Tomatoes, but next year I'll do tumbling toms (I think they're better adapted to containers and more compact so I'll have more space for other things! this year space was a problem...).
My only perennials are alpine strawberries and a small 'TopHat' blueberry (all suited to containers), plus violas but that can't be a staple food. Rhubarb sounds great Principia I'd go for it! Plus, you can use the leaves to make a brew that's good to tackle aphids...
I'm toying with the idea of growing asparagus - another nice to have perennial, if only I could manage it...
Best of luck with your future plans and enjoy the strawberries!