Knowing who Sinclair is is largely immaterial for a good chunk of S2 and S3....
But then that guts the impact of understanding:
1. Where did Sinclair go(and then understand behind the scenes about the medical issues the actor was facing).
2. Who Sinclair becomes.
If someone watching for the first time skips S1 then they would probably wonder why so much attention is being paid to this 'new' character.
I know when I saw who he became I was floored. Didn't see that coming at all. Then combine that with the fate of B4. I agree that S1 is rocky(as many S1's of other series were back then) but these episodes and getting to know Sinclair do have a huge pay off.