1. Go for Roshi

2. Mood +life and watch him wok

All jokes aside, you were misinformed about future usage between the two. Rohsi is absolute endgame. Regardless of ninjas and meta shifts. He will always retain his value. Han other hand is very niche and rarely seen in CN. Although Han, is pretty useful, by removing buffs and tanking. My biggest issue with him is that he doesn't scale nor is he immune to debuffs (ignite,poison, paralyze,etc...).My experience with Roshi since pulling him has been amazing. Granted I am pushing close to 90k but I was only at 74k or so when he came out. He carried my space time fights. Beating people with 15-20k more bp. Fights that seem impossible. My losses came from people with higher bp mirroring my team lol. That says a lot. Like Petrichor stated above me, this is due to his outplay potential. If he isn't taken out by blitz teams then he gets tankier and stronger over the course of the fight. That is dangerous to anyone especially when you pair him with earth or water main. With that being said, go for Roshi first and then if you would still like Han, I would suggest going for him afterwards. Also, I know his chase is a bit intimidating but he functions well without it in certain line ups.

P.S.- I think my post is heavily biased. I would like to add, that it also depends on your playstyle and most importantly your ninjas. Best of luck!