Were Xenogears and Xenosaga supposed to be related at all? If they were I definitely don't see how I hadn't played Xenogears before Xenosaga, so I really enjoyed myself.
The plan was for the creators of Xenogears to produce episode 1-7( or was it 6 ? ) under the name Xenogears. But square i guess ignored them or shelved the IP for years and they got tired of their BS and left :/ something along those lines, they wanted to stick with the original plan but SE did not sell the rights to Xenogears, so they had to make Xenosaga, which means they could no longer follow the plan they had in Perfect Work etc etc. So they still used the same Mythos and ideas but with totally different characters and story. Also what happened with Xenogears as far as the second disc was, that Square was behind in FFVII so they shifted resources and personel from Xenogeares to finish VII, and that is why the second disc of Xenogears is as it was ( Which i did not found that horrible, i was already tired of grinding by that time XD!)
As far as Xenosaga, EP 1 was solid, 2 was very Meh! and 3 was awesome <3 I really which SE would get the xeno team back and do a remake of Xenogears as it was intended and release EP 5 (Lacans Story)