Hmm, tricky - but can be straightforward if you are prepared to step back and be clear within your mind about what you expect him to do, and are Ok with if he doesn't - then approach him once you are clear what is fair. That way you shouldn't be taken off guard and will know whether to argue more or accept what he offers!
Fwiw a lot of rented places are like this - I've always liked the freedom to do up a place a bit, without the pressure of keeping painty handprints and cat hair away from the pristine refurbishments
But it can get really annoying when everything is dirty.
Two things - if he wanted to do the place up, he could then presumably charge new tenants much more money - you said you had a good rent? - so he could do that if he wanted. Then you might be out of a home.
OTOH he might just be being lazy, using you as an easy tenant, because he can't be bothered to do it up.
I think in most cases you do get what you pay for but structural things, flooring, etc if it needs repair, really ought to be sorted as he can't expect you to live with that sort of damage - that's just unfair.
So find a premise on which to approach him - I would offer to contribute, myself, or get cheapest quotes etc. See what he says, there is no harm in asking.
I'm just taking on another place in a state - but I enjoy the refurbing myself, am a bit weird!! And it is very cheap
There's no reason to think there will be any bad feeling ime.