I think now is your chance to caught up to this game series, it is worth it in my eyes :) I loved KH 1 and 2 on PS 2 back then, and as soon as I am back with my PS4 later in summer I will get my hands on the remakes. I have the KH 1 Remake for my PS3 but played it just for a short time, so I assume I will have to replay it on PS4 now to get ready for KH3 :)
Also Birth by Sleep was really good, but haven't played Chain of Memories yet :/