THere is nothing so bad, almost, that you couldn't fix it, if you have the time, the skills and the cash. Its just frustrating to have to do it.
You can use pulled rivets in the triangular brace below the roll bar but that looks like too many and they look non-structural. Also the line of rivets isn't straight. Why does the hinge piece go all the way around the firewall? HTat's not what the plans show. The little holes in the corners of the wootwells are hard to impossible to avoid and just need some sealant, but the lack of edge finishing ideed suggests a lack of care, so what else is poorly done? Arlie's list is a good one - especially the point about over countersunk holes for the fuel tank attach on the spar flange, and the edge distance on the engine mount weldment bolts..
You MUST (I write this with feeling!) get someone who has built and flown an RV-4, to look closely at it. If there is any doubt about the kit and you are not confident that you can fix it, walk away. Like some of the others here, I bought a part built kit, spent money trying to remediate when it was really scrap, and eventually gave up. THe vendor is still refunding me money......
Good luck,
Chris