I haven't noticed any extra drag due to the unfilled weave, but I'm not know for my delicate touch on anything, either.
Same issue with buying any paddle online... I like to take a good look at it, feel it in my hands, feel how much flex there is... and of course, how it looks on the back side.
I have repaired splintered paddles without making new cuts, but success is very touchy. If you don't locate every single little defect in the remaining grain, it's just another split waiting to happen. I've repaired a paddle for my local Forest Preserve District (a 6&1/2 foot monster, used for their 34 foot Voyageur Canoe programs) several times, and it has fallen to this problem every couple years or so. Whenver it needs work, I force the splits open to see how far they go... usually it's all the way through, and I get a multi-piece puzzle to reconstruct. The last time I glued it up, I put a fiberglass sheath on the shaft to give it more strength. A few weeks ago, after I'd stripped the cast off it, split it apart, and glued it up again, I stress tested it by flexing it... and I had a new puzzle in my hands! This time I split out a lot of pieces, glued it all up, and casted it all over again. Stress tests at every step indicate it should be good to go... hahahaha When it breaks again, it'll be left in pieces, and we'll make a cross for a tombstone, to be used as a new prop for the Voyageur programs. And then I'll just make a new one.