I've been on Louisa twice, and would love to go back again.  It's always nice to get out of the lower Agnes bottleneck onto a less popular route.  I'm recalling that the campsites we saw were very exposed, but we only saw a couple.

If you enjoy smaller lakes and creeks, a day trip to Glacier would be worth it.  I'm also unaware of a long portage, but have taken the several portages to get there.

As to wind, I guess you can get it anywhere and it can be dicey on any large lake.  Agnes gets the reputation mainly because of the length the wind/waves can travel up or down the lake with minimal obstruction added to the general populairty of the lake.  The high cliffs also seem to funnel the wind.