I agree with you on that. I don't rate Kone either. The problem is that we spend £5m on a striker here and then another £5m on a striker there and so on......and all we end up with is £5m strikers. They just aren't going to get results.
We should have saved the £10 million or so that we spent on those two (Jelavic and Kone). We could then have afforded some like Van Wolfswinkel (not necessarily him but someone of that calibre for that sort of price tag). He'll score more goals than Jelavic and Kone combined.
Or, we could have sold Felli and added the £10m to his sale price and we would then be looking at the Negredo's, Soldado's etc. I guess the point I'm making is that if we only have a little to spend it's better just to keep it for now or repay a bit of debt as spending it on a striker is not going to achieve anything as we won't get a decent one for less than £15m ish.