Our slide awnings haven't been much trouble in this dept., though some pooling has been minimally annoying on occasion, as has icing. Our '06 awnings have a bit of a slope to them, so 90% of the time rain runs right off. Perhaps maintaining or adjusting the fabric tension would help, though when I asked about that regarding stopping the flapping noise during nighttime wind storms, they said there was little to be done. I'd rather put up with a little pooling than bring in a slide with a lot of water on top, so probably wouldn't go with Bill's solution or mesh. Have to agree though, after heavy rainstorms that overwhelm the toppers' runoff capacity, resulting in pooling/sagging, the subsequent mud splattering onto the coach upon slide withdrawal can be annoying. But after a heavy storm, there is rain mud spatter on the lower panels anyway. I think I'd explore adjusting fabric tension any safe way I could.
I'm not sure adjusting level with the slides out is that big a problem, though there is certainly a side that argues it. Contrary to most RV manufacturers, Monaco instructed that slides be extended prior to leveling a coach. Given that, maneuvering air or jacks slightly to drain water off awnings shouldn't be that detrimental.