That may be his definition of normal, but I'd say it's not typical and not my definition. Lots of pools have a small drip here and there. For example, on the multi-port selector valve on mine, right now there is a slow drip. Not worth screwing around with something that leaks a pint a day, outside, where it's not a problem.
Also, here we winterize so there are various plugs that have to be removed and re-installed each season. If one of them has a tiny drip, I'll tighten it, but if that doesn't work, I'm not about to take out the plug on the bottom of the filter again over a pint a day drip.
You can drive yourself nuts over trying to make everything perfect. Some people seem to think you should tear the whole thing apart just because it's not plumbed pretty and it's harder to repair. I think they are seriously underestimating the amount of work involved. And for what? It's working, isn't it? And you just replaced a valve. If there comes a time when there is a major overhaul, eg you're switching to a DE filter, then I'd consider what can be changed at the same time to make it a better design.
As far as using flex pipe instead of elbows for efficiency, I wouldn't worry about it. Rigid PVC is cheap, sturdier, last longer etc. And those elbows don't amount to that much in the grand scheme. You just minimize their use where possible, use 45's instead of 90's if u can, etc.