I recently had a trip with a new FA. She remarked to me, in front of the CA, "I feel like I have two Captains in this trip, you're really helpful". I was mortified. Then the CA chimed in, "That's actually what we want. FO's will be Captains one day and they need practice thinking like one." I felt a little better at that point. However, I'm here to help. I'll acquire any info you need and provide any support necessary, but there's a chain of command and the occupant of the left seat is still one link ahead of me.
I feel ya. Couple captains, who are also current references on apps, have said "I can tell you were a captain prior to this." I was similarly mortified and my eyes went grew large as saucers. However it wasn't as bad as I first thought after exploring the feedback. Doing things like "hey I'll see whats going on with the paperwork" 15-20 prior, and while taxing the captains trying to do 3 things at once I will say "I'll get the PA for ya," and solving passenger problems with gate agents and FA's so the CA can keep talking to DX or MX or whatever. That sort of stuff was effortless for me because it was second nature, and apparently I did it in such a way it didn't intrude.
When I was a young FO, and I'm sure
@Seggy (and another poor CA who told me one day, "I can't tell what's worse, a new 250hr FO or a FO about to upgrade.") can attest, I did a lot of right seat captain because I was worried about the upgrade and I really wanted to get into the head of a captain as much as possible. That turned into lots of feedback for the poor bastard I was flying with and none of it was helpful. The problem with 2000 hours and energetic, is that you can step on a captains toes easily. After being a CA for 2.5 years and stepping back to the right seat, I learned what a good FO is, a right seat CA. I still needed reinforcement and mentoring from CA's to make sure I was doing what was helpful and not overbearing, but picking up slack is so much easier when you know exactly what the guy next to you needs. That means you're going to make some decisions on your own.
The difference was experience. Except for a few diamonds in the rough, a good FO is a former CA (not a downgrade). Now I'll admit, since about Dec of last year in the -200 I was about to hang myself and my work ethic showed. If it didn't it was only because I went through the motions well. In fact I don't know if I ever fit in on the -200 at Endeavor (the pinnacle side) but it's impossible to know because moral got worse every trip- a statement reeking of hyperbole, but it's not an exeraggeration. The Pinnacle guys weren't bad guys, but they had PTSD (Post Trenery Stress Disorder) and it kills everyone's buzz.
A right seat CA (good type) can be an asset. If a guy missees a checklist I just run it and say it's "complete". That's not a flipping challenge to anyone's authority, you missed it, I pick it up. I hope to God you do the same. Mesaba begged for that, Pinnacle doesn't need that sort of adult behavior in the cockpit. Ask the guy you've now spent 15 legs and 18 hours in the cockpit with if it's ok if you chime the FA when it's CAVOK. Or when the temp dumps to -8C and the cowls still aren't on IMC. How about I just throw the switches forward and say, "Cowls on for ya." Jynxy, you sure do tell a lot of stories! Wait, you're going to miss my conclusion. A right seat captain can be a good thing for the real captain if he want's help.
So you have a bad right seat CA, a good right seat CA, but the good right seat CA can only be that if the real CA isn't going to shut FO down for making decisions (sometimes wrong ones) on their own.
PS: yes, there are FO's who exercise poor judgement, but that's 5% of your FO's. Mostly they just do things a little different, and different normally isn't bad. A good CA will show that FO where his choice could be even better with a little mentoring.