he is viable in a competitive setting, its just that he is very difficult to play at that level. honestly if you do enter as siegfried, i would hope that you choose a secondary character to compete with as well (your sophie) for the exclusive purpose of defeating ivy and sophie. sophie is easily siegfried's worst matchup at 8-2, meaning the only way you're going to win is if A) the sophitia player doesnt know the matchup, B) you are extremely lucky and played extremely well, or C) you outclass the sophitia player in terms of skill by a couple of miles. ivy on the other hand is 7-3, and while sieg has a couple of these, and the fact that he can compete alright with ivy in the hands of a seasoned player, you yourself have the ability to use sophie, which would save you a whole lot of heart ache which is caused by that matchup.
but although these are two relatively steep obstacles, sieg is completely viable in competition because he is adaptable due to the fact that he has a good amount of tools for a good amount of situations, he can space out most characters very easily, he's difficult to punish at far range, has strong SG, has a good amount of mixups that help penetrate through the opponents guard, he has an obscenely strong CH game, and one of the best TC launchers in all of SCIV. his weaknesses are his slight lack of speed, his lack of safety, and the holes in his offense that are created through weak spots in his stances. his oki game is average, but his wakeup game is very strong if your opponent is dumb enough to stand up against you. he's surprisingly strong at punishment, and very strong at whiff punishment. all you need to know are the holes of his stances, and how to close those holes.
you also need to know specific strategies to combat each character, particularly revolving around either spacing or rushdown. and you need to use some very high level mindgames if you want to be successful.
so basically your focuses should be:
- CH fishing - this is the bulk of your damage. period. siegfried is fairly weak on NH. 3B. use it, love it, and for the love of god, do not throw it into your opponents guard unless at tip range. if you're throwing out alot of blocked 3B's, you're doing something wrong.
- Spacing - moderately far range, but not quite tip is preferable for offensive strategy, tip for safety and poking, close for rushdown and mixup
- Mixups - goes hand and hand with spacing
- Mindgames - these basically enable your mixups. they also allow you to bait for whiff punishment, which can also lead to mixups on wakeup, or some oki mindgames. this can also include SG damage, which can bait unsafe moves for punishment. also, make your opponent earn your respect of frames.
- know your own weaknesses - if you know when and how you can be retaliated against, especially while in stance, then you can learn how to set up situations to deal with it. know what stance can be stepped what direction when and how. know what's safe, know what's not, and especially know what your punishers are. also siegfried may have very strong verticals, but you have to remember to control your opponent's step. not that you need to kill it every time, but if you can make your opponent fear stepping with tools like iagA, 6A, 3A, and CH iWR A/AA, it allows you to abuse your stronger moves with more confidence.
Sieg is pretty solid against most of the cast. he can even compete against his 6-4 and 7-3 matchups fairly well if you play your risk, reward, CH fishing options properly. if you still need further convincing, i'd look at some of the vids from competition that include pantocrator, synraii, or sacharja; or better yet even try talking to them about strats and the like.
Of course, if your going to compete with him, you probably already knew most of this, if not all of it.
So i'd definately say he's effective and practical in a competitive setting, but he definately requires alot of work and knowledge to win, which does indeed make your life a little difficult. that, and pray you don't meet a sophitia player.