Every time I have used the service it's empty Ashford to Hastings then full from there on. As I travel Ashford to Eastbourne I am happy..... splitting the service at Hastings would be no benefit to most people, potentially causing the termination of this useful service.
To say it's empty to Hastings is slightly unfair. Whilst there definitely are times when it's very quiet (like the 08:53 Ashford to Hastings stopper which I've seen pretty empty a couple of times), the two car trains are typically "well used" on that section (i.e. comfortable and exactly what the two car units were designed to run). Ham Street is a reasonably well sized village and Appledore (despite seemingly being a long way away from either civilisation or Appledore itself) seems to do alright for itself. I have a feeling Winchelsea could do better if it was served hourly, but it would of course still suffer with being a little way away from the village. Naturally it's the bit beyond Hastings which causes trouble, not aided by the fact that it's the only fast service between Hastings and Brighton.
I agree with everybody else; four cars all day everyday on the through service would be great. Realistically however, I see it remaining as it is for quite some time to come. The first step will hopefully be to see more four car workings on weekends (good progress towards which we have seen this summer), then (if such rolling stock does become available) four cars all day everyday before the eventual goal of electrification (and hopefully the improved service which that would allow).
I think in an ideal electrified and sufficiently redoubled scenario, there would be two trains an hour on the line: the current Brighton-Ore stopper extended through to Ashford with calls at all stations (perhaps Doleham excepted for most of the day), allowing the Ashford-Brighton express to no longer call at Winchelsea or Three Oaks (and dare I say it, to skip Eastbourne via a reinstated Willingdon chord). Whilst this seems a little bit "pie in the sky" now, it seems a lot more sensible than running Javelins to Hastings or Bexhill in my mind.