Hard to say... You get Vander, Kagetsu and SEADALL. Not having a flier early on does suck to be sure.
Apparently, the AI detects that both Alear AND Framme (using Chain Guard) receive damage without dying and attacks Framme because the target - Jade - won't counterattack. If Alear equips a 1-range sword, a nearby lance user tries to break her, and if that attack connects the archer will try to go for the kill. However, with the levin sword equipped, the archer acts first and ignores Alear... It doesn't really have anything to do with my using Obstruct.
Chloe probably could've got more experience, and with it SP, if I'd prioritised her for arena experience and rigged her multiple instances of Vander combat for, like, 150 exp in between each chapter. Because of her role in slaying bosses in just about any map when she's available, she can't really afford to equip Emblem Marth and kill things with Mercurius for experience. Even for Alear, there was only really one map where I could've used that (chapter 6), and I abstained because I didn't want to rig one level-up too many. In general, having fixed or modded perfect level-ups would remove the dependence on rigged levels and allow me to care about the quantity of experience over quality of level-ups. Until chapter 19, Alear is the only one who can Canter.
WRT the well, things don't seem so clear-cut. I wish I could compensate for Seadall's absence with, like, extra Warp staves, but at the same time I haven't been utilising the well for many maps where, were I to play it now, the well might've helped me some turns and made more objectives possible. I'll probably play around with the well and see what I can get but avoid any real manipulation, much like the Fates lottery feature.