Well, it's an idea. But while there may be people willing to put their lives, careers etc on hold to spend a couple of weeks on jury service, somewhere fairly local to them, I think you'd find it exceptionally difficult to find people prepared to effectively up sticks to London for 5 years to be part of a legislature selected on jury-style basis.
And, sure there are plenty of useless MPs. But I really don't like this 'they are all the same, all as bad as each other' narrative. There are plenty of really hard-working and exceptionally effective MPs - and that is across all parties. But there is a difference between the job of a constituency MP and that of a minister and the government.
There are many good MPs but much of what they do that is good isn't really seen. The gong show in the HoC seeks designed to make them look like idiots, though some make special contributions to that effect.
Those debates when the House rises to the occasion, infrequent, and are often after cock ups by numerous executives- see the debate on the Horizon fuck up.
Add to that the various expenses issues, the subsidised pubs and restaurants in the HoC, the huge unwieldy patronage of the HoL, and the system looks indulgent and decrepit.
I'll be interested in the turnout at the election, current betting is that it will be below 64%, and I suspect many voting will vote with little enthusiasm, and often purely against certain parties, rather than for anyone. And, of course, FPTP had its own issues there.