Robbie Jackson was a waste of space, I doubt he's the answer (or at least part of the answer).
Personally, I think it's time for a smaller family unit to offset some of the focus on the EE legacy families (the Mitchells, the Fowlers, the Beales). I wouldn't have mind Star and her mum being brought back. Her mother seems like a complete nightmare, which would make great drama, and the actress playing Star is talented so there's potential there. In fact if they did bring them back, maybe there would be a possibility of getting Jay's name knocked off the sex offenders register.
Having said that, I don't think bringing back one single character is neccessarily the answer. I think what's needed is balance (no more Carter centric episodes filled with nonsense, please) and good storylines. Since 2006 EE has produced some excellent episodes and storylines. Stacey's bipolar storyline of 2009 was fantastic, as was Syed coming out (2010). The episode in April 2010 where everyone finds out Syed is gay and has been having an affair was fantastic. Brilliant acting all round, especially from the actors who played Amira, Christian, Masood, Zainab and Syed. Similarly Whitney's abuse storyline was fantastic. I also thought the storyline about the sexual abuse Ronnie had suffered as a teenager was fantastic. It was short and perhaps came out of nowhere, but everything was revealed in good timing and there were great scenes with Ronnie and Roxy. The Stacey/Max affair was brilliant. All of the above storylines are fairly non-convoluted, but they featured good actors, the pacing was well balanced and just right, and the writing was strong. Serious issues such as religion/culture, sexual abuse and mental health were handled with integrity. EE had the opportunity this summer to focus on an interesting storyline about homophobic abuse when Paul was killed but this was undermined and badly handled: the story ended up being used as a vehicle to parade Grant Mitchell around as a 'tough guy'. Talk about asking viewers to suspend reality...Similarly Kathy's return was crap because it was badly written. It was a headline grabbing story with no substance and fully of gaping holes and has forever destroyed the character.
There are some interesting story-arcs on EE at the moment: Lee's depression has been slow-burning but devestating to watch and Denise's storyline is also interesting, especially as she has been criminally underused. But plenty of other characters are being underused and potential is withering away. I personally think they need to do more with Louise rather than have her standing there as a sassy, bitchy teen. She made a comment ages ago about fancying her maths teacher - that could be interesting. A teacher/pupil storyline, not really been done before, but if written well could actually develop the character. Because right now, she's not actually doing much. With Ronnie/Roxy going there's a gap in the Mitchell family, and they really need to develop Louise or indeed bring back Sam Mitchell. Johnny Mitchell seems to be doing a lot of standing around and being generally useless. They need to get him with Steven (in an affair storyline preferably) or Ben quickly. Similarly, Abi has been purposeless since April. As has Donna. As has Vincent. There's characters screaming to be used, but are being ignored.