@brunocar you're not alone brother, I used to think tsubame would be better but overtime I've quite warmed up to the iino and ishi ship. I think they make a great match and ever since ishigamis flashback I had a feeling they'd end up together. I honestly predict that tsubame will accept his feelings and 'confess' but it will either be an issue because ishigami doesn't realize he confessed to her or tsubame says something along the lines of 'I like you but the person you like isn't me, is it?" Ofc, if he ends up with tsubame that would be great too but I'm pretty sure the storyline is leaning towards ishixiino.
I think the main anchor for that iino x ishi ship is we don't actually have any character depth to tsubame yet. Perhaps we'll get it with this arc and it's possible if we ever do get a tsubame arc I'll jump ship to her but we'll see.