I unfortunately don't have experience with the Langrisser or Growlanser series so the idea of a reboot doesn't ring any nostalgic bells for me, and I've heard that the real fans of that series are also not really into the idea of the reboot. Looking over the gameplay, it also looks too similar to Fire Emblem, which I just finished playing. Pass.
Ray Gigant looks interesting. I have mixed experience with Experience DRPGs (hohoho), they're hit or miss to me. The main attraction for this one seems to be the very pretty in-battle character graphics - they definitely do look nice. I might come back to this game if I end up finishing Trillion with time to spare before Yoru no Nai Kuni comes out.
While I was buying Trillion, I saw that Sega already has a giant display up for the new 7th Dragon game which doesn't even come out for another 3 months. We'll have to see if game quality is affected after Sega takes over all of Imageepoch's old IPs, but one thing I can say is that they advertise well. It's going to be a busy remainder of 2015 for JRPGs - after Trillion I have Yoru no Nai Kuni in late August, then Atelier Sophie and Utawarerumono in late September, and 7th Dragon in October. Star Ocean 5 and a half-dozen other titles are also looking to be late-2015 releases. The first half of this year was pretty dry, but things are looking up for Q3 and Q4.