there are more irregular verbs than just kuru and suru. iku and aru are also irregular, for example.

Irregulars notwithstanding, the conjugation pattern is actually completely lossless if you just remember the imperative form (e.g. 着ろ kiro, 切れ kire) instead of the infinitive, which is lossy (e.g. 着る kiru, 切る kiru). Then there's no need to have to remember, "oh... is this -iru verb group 1 or group 2?"