So my group and I have been trying out a bit of Zodiac, and we've found that the strongest characters are the ones that exclusively focus on Magic plus Spirit. Tech levels being dependent solely on Magic means that other character builds (focus on agility, or strength based characters) just can't keep up in both ability variety and strength. It's also a bit puzzling, as it forces characters that might not normally have any need of magic, (warriors and rogues who want to remain physically focused for example, or other characters that might not flavor themselves as magical) to invest in improving their magical skills. And there's only so many variations on enemies that are resistant/immune to magic, venom, poison, dsentence, stone, fatal blow, near-fatal, etc, that spam seal, before it basically comes down to sending dedicated anti-magic builds that exist to give the other characters something to do.
We've been thinking about adjusting the system so that tech points are based off any one of the five base stats chosen at the start of the game. This allows characters to choose a "focus" and be rewarded for investing in that focus, without being punished for not picking magic. Would this be a reasonable house rule?