Don't worry, there is no way to do good as a viper in P1 and P2, i've killed FRU 4 times as a viper, i played well everytime, and everytime my team had to carry P1 and P2, viper and machinist are so bad that it looks nearly impossible to take them in the team if there is no broken pictomancer to compensate. And you can still consider yourself happy cause machinist is even worse, at least the viper is good in P3 - 4 - 5. I really don't know if there has been a single time in the game when such a lack of balance has occured : picto in ultimate is the most broken thing i've ever seen(at least in P1 and P2), while viper and specially machinist are so trash that they can't even play without a picto in the team.
Oh and in addition, that's not the subject, but since we are talking about the viper, i'd like to add that currently, the viper also has the biggest problem in term of gameplay : since they removed Noxious Gnash, the viper's whole combo system is totally broken, the viper only uses 4 of his 8 possible combos in a full uptime scenario, while SE has made an entire UI for it. I think Noxious Gnash in its previous state was absolutely awful, i don't know if removing it entirely was the best choice but i understand that they did it because it was terrible to use in any situation that was not a single target full uptime. But now that they removed it, we lost half of our rotation.
So they should absolutely make something, like easy solution : reaving fang should give a TWO CHARGES buff(or resource without time limit) that buffs steel fangs two times. By doing just that, they would alternate in a reaving - steel - steel loop, the viper would get back his 8 combos, and those would work in a 12 combos cycle that would loop every around 2 minutes. Everything i said should have already been done in patch 7.1, we're now at 7.15 and nothing has been done while other jobs like ninja, samourai and dragoon got buffed while they were already stronger than viper, i hope something is done really soon because it's starting to get frustrating.