It largely depends on the group as to what the reaction will be.
I think their potential attitude to change would be pretty easy to predict based on a few nets with them.
Its probably best to approach your captain after a couple of nets and discuss plans for the season.
Do they have targets? Promotion? Survival?
What are they putting in place to achieve the targets? Structured training? Commitment to training?
If he doesn't have many answers, then drip feed a few suggestions, see what he thinks, if he puts them into play them brilliant. If he doesn't, approach him and the committee with your thoughts in full.
Some people can reject help/input i they see the person offering it as a threat, so you need to make it clear you aren't there to oust anyone, you just want to be part of a successful, ambitious club