[Baalz]

Hmmm, you'll get N4 capricorns often enough, but to cast mother oak you have to have N5 - on land. Since you lose a level going on land that means N5 in the water plus a thistle mace. You've got less than a 1% chance on each capricorn to get N5, so essentially you're scrapping the mother oak early strategy. You're also scrapping the llamia queen farm, and by extension much of your death magic and all your blood magic. You can still squeeze into death using your pretender, but it's an immensely steeper slope to climb than using your nature gems (fueled by the mother oak) to summon mages, while you use your limited death gems to site search. If you're using your limited death gems to summon mages with your pretender this drastically slows how fast you can site search.

As I mention, N5 is an expensive thing to do, but I think what you get justifies the cost. You very likely get hundreds of nature gems from putting the mother oak probably before anyone else can cast it and well before anyone is likely to try and dispel it. You get very solid entry into death, and a respectable one into blood. The alternative suggestion is to go with astral, I just don't see it bringing nearly as much to the table.

As to going for constr-4 first I think this is an expensive thing to do. I look at it this way, for your first engagement you're unlikely to have two mid level things researched, so would you rather have constr-4 or alt-5? Alt-5 brings numbness, quickness, wooden warriors, bone melter, encase in ice (perfect if your opponent has a SC god underwater) and swarm (perfect if your opponent has a SC god on land). Constr-4 certainly does give you a couple nice things, I just think it's better to focus on what gives you the most bang for the buck.