But alongside these Angels, won't there be some permanent Raid Event feature? So, instead (or in addition) of using Eidolon Orbs and Orichalcos, the player can have easier access to past Eidolons, Raid Kamihime and Weapons.

I mean, if that is the case (not sure), it seems to be a good compromise - weaker Union Events weapons in exchange for permanently available past content.

The Union Events don't seem to be that noob-friendly anyway. Maybe DMM thought, "new players feel bad because they can't get those sweet weapons. Maybe if the weapons were a tad weaker, these people wouldn't feel like they are missing out on content". Dunno, maybe they made their marketing research.

Don't get me wrong I like my Assault and Pride Weapons with cool burst effects, but those weren't easy to get! I could build my grid faster if past Raids were available when I first started.