The Jemini song was perfectly fine; obviously not the tunelessness, though, whatever caused it! I actually really quite liked the Engelbert song itself, but it was more a laid-back 'schlager' style song and never suitable for Eurovision.
I'd love to see Sam come back. He already (effectively) won it once, so why couldn't he be the UK's Johnny Logan?!
It's no good sending in a perfectly decent tune, though - it has to be outstanding, memorable and performed with huge energy. Sam did that and was a massive success. I think a lot of people don't seem to grasp the fact that it isn't only rubbish songs and/or performances that do badly - you could be every single country's 11th favourite (so well into the top half) but not get a single point.