
Actually, that's exactly how they were designed from Radirgy onwards. (cf. this interview translated by shmuplations)
Talking crap about Milestone games for being too easy while you stayed behind your shield the entire time is like complaining that 2-min/5-min caravan modes in Star Solider games are easy to clear. That said, it is true that these games are not for everyone. But the same would be said of any shmup, really.—Why did you decide on another STG for your second title?
Kimura: We had decided that we wanted to do at least one STG title per year. There was no special deliberations or anything. (laughs) But our approach to creating Radirgy was very different from Chaos Field, so its concept was entirely different too. We wanted an older “Caravan STG” atmosphere, with a high-risk, high-return scoring system woven in.