I think the issue is that it breaks the math of the game. Scaling d4s is a lot, and I would say it would be much more reasonable if you replaced the scaling d4s with proficiency bonus, which is what the math of the game is based on. If your group likes rolling dice, try scaling it with a singular die that increases in size, ala bardic inspiration.
Sure, it would still be powerful for rogues, paladins, and maybe bladesingers and hexblades, but it wouldn't massively outshine the other blade cantrips, at least if you don't build yourself around this modified truestrike. Without the expanded crit range, I can't imagine anyone other than a sharpshooter rogue taking this. So really, you just need to adjust the numbers.
Compare:
lvl 1: +1d4 (avg 2.5) vs +2. Crit range avg 17-20 vs 18-20
lvl 5: +2d4 (avg 5) vs +3 vs +1d6 (avg 3.5) . Crit range: 15-20 vs 17-20 vs 16-20
lvl 11: +3d4 (avg 7.5) v +4 vs +1d8 (avg 4.5). Crit range: 12-20 vs 16-20 vs 15-20
lvl 17: +4d4 (avg 10) vs + 6 vs + 1d12 (avg 6.5). Crit range: 10-20 vs 14-20 vs 13-20.

So yeah, 1d4 -> 2d4 -> 3d4 -> 4d4 is just too much. Proficiency bonus, bardic inspiration scaling or 1d4->1d6 -> 2d4 -> 2d6 are all within the realm of numbers the game is designed for, while still being powerful.