If it is just the matter of leaving an impression, Hulkenberg can easily leave a strong impression while racing for 5th and 6th positions as well. After all, in terms of 2015 silly season we are talking about him moving teams once again, be it from Sauber, FI or Lotus. And people in the know already have an idea, how good he is, so 3rd, 6th or 10th position doesn't change opinions that much. On occasion Force India can do what Sauber/Lotus have done and threaten the top as well. In Brazil last year Hulkenberg was challenging for the win. In late 2009 Force India was very good and you could get the feeling that after the Belgian GP and Fisi's second place the car potential wasn't maximized properly. Also di Resta was fourth in Bahrain this year, being in contention for podium for some time during the race.
I think the "impression" that Sauber, Lotus and Williams could be offering better cars, lie largely in 2012. But we will see with 2014 regs. In 2008 you could say that Renault has a greater chance of offering a more competitive car than Red Bull just because Renault had a proven track record in 2005-06. But it didn't quite work like that. When we predict 2014, we can't predict based on past terms and impressions. It will be a clean sheet.
I think Force India is a bit underestimated. I think Hulkenberg can get a podium in that team as well, if not multiple ones next year. Especially in a wet race. We will see, but I don't feel FI has less depth in the team to shine than the other cash-strapped midfielders even when we are talking about "highs", not just median consistency. So far yeah, FI hasn't got any podiums since 2010 unlike the other three, but it could change. F1 is always in change. FI/Spyker/MF1 had got only 1 point during 2006-2008 and it may have seemed they can't get out of backmarker status, but they did.