I think you need a bit more time and there are currently better candidates who have been working towards this position for a lot longer. For constructive feedback you said it yourself, be more active on the forums and speak more in meetings. I will also add that there are times when you can act a little immature as well. Apart from that good luck tho.

I do also want to add that i do not think its best to join train of people applying for super admin just because some former super admins have left. I feel you should apply when you believe you are ready, not just because a spot has opened up.