So lets say I want to make a character with such techniques, does the system burst into flames or can it be done?
Note: I'm the Mentalist expert at my table and no one seems to have a solid grip on building techniques.
I know the pattern is usually 2, 2, 1. I'm thinkin of using Dio Brando as inspiration for the F/X and effects, like weapons appearing en masse to attack from multiple directions, moving without appearing to cross the intervening distance, and some kind of "youre dead a d dont even know it yet" maneuver). And maybe another technique that mirrors the Arcana Shepirah power that lets you accumulate Zeon or buff, but this would be for Ki.
Too much, way easy or what?
You don't need Techniques to do some of that stuff, but you would if you wanted to do it at low levels. Look up the Ars Magnus section in Dominus Exxet.
"weapons appearing en masse to attack from multiple directions"? Ophiucos, the last of the impossible weapons.
"moving without appearing to cross the intervening distance,"? Infinium.
When it comes to techniques, there's always stuff like Automatic Transportation, or for the multiple weapons thing, you could use Additional Attacks + Indirect Attack. You can't "timestop" per se, AFAIK, but each tech has some fluff that describes how it looks when activated, so you can always say that time appears
Hope that helps.