Am I A Bad Parent?

Their values can go up as toddlers. Having their parents help them perform a lot of actions that positively boost their character values will help.

The only character values that I've been able to raise are polite and responsability. All the other, even trying hard I never could raise to the point of getting a trait.

No matter what options my sim parents selected for their toddlers it didn’t mean anything until they became children. And even once they became children I found you don’t actually need parents to influence children. There is plenty of in game objects children use which you can use to push the values.

Yep, it feels to me there's not much the toddlers can learn. Most of the time, when my toddler ages up to a child, it's around neutral on all aspects.
At child stage, it's good to have twins (or 2+ kids close in age) as they can buff empathy and emotional control by talking each other out of the random school events (if they give sad/embarrassed/tense) and, eventually, teen mood swings.

I don't have the Parenthood yet--still considering--but, dang, that sounds exactly like real life. Toddlers do not do emotional control or conflict resolution, and grown-ups who expect it of them will probably be disappointed. They might do some very easy chores like putting things away because that's what Mommy or Daddy are doing or because someone turns it into a game, but not because they feel responsible for taking care of their things. ^_^

Teaching them to 'Say Sorry' (under the Parenting options) builds conflict resolution, IIRC (or emotional control - it's one of the two). Teaching them to 'Say Please and Thank You' builds manners (and the talking skill). I use the latter quite often. It doesn't have a huge effect, but they get a little bit of green by the time they age up to kid. You can also get credit for 'discipline your toddler, kid or teen 5 times' aspiration goal by 'Encouraging' the child to learn to say please and thank you after you finish that action. (It's available in the Parenting menu after you teach the child to say please - it doesn't matter whether you finish or the tot rage-quits on you.)

Disciplining a toddler for doing something wrong will build a bit of empathy, at least if you use the mild or firm responses. (Not sure about the strict, since I usually stick to 'firm'.)

It's not really that important when they're toddlers - it's more when they're kids that you have to start worrying about it. I do whatever parenting I feel like when they're toddlers, then when they age up I have to be more careful.