the problem with the daddy's son teams is that without their presence the series loses what, 4 teams and 4 fully funded regular drivers immediately. their presence reduces the market of available seats and as such means that there's less likely to be cut price fill-the-seat-at-all-costs gp3 style drives around. all round in a very indirect way it keeps the series afloat and the reputation intact, particularly since none of the sons-of are woefully slow. just not very good
that said, a returning champion is great news for the competitiveness of the series - it's easy to spin from a pr point of view and you can argue it makes sure everyone brings their a-game in a similar way to having current and past world champions in f1 does, albeit on a smaller scale. after all, aleshin beat ricciardo. and going by racing driver (and dad) logic, if you can beat the man that beat ricciardo, you must be a god, right?
(however, on the aleshin front, the fact that he wasn't on it straight away in hungary last year did really demonstrate for me the importance of the engineer/driver thing in fr3.5 - as per alex's point about a driver coughing up to bring his own)