Thomas, Are you suggesting that the font is a tremendous improvement because the font does not have any ligature? This is a sincere questions, not to belittle you. I would like to share my experience in this regards. Although I'm neither a professional font developer nor expert in the field, I do find a problem with fonts without ligature. Of course , this can be solve, but need some consideration.
Actually, I've done some work on this to the extend that all typical ligature is replaced, and I would say the font I develop is good. The font does have more alternatives then just lam alef sequence. I've sent a screenshot of the font to Mete, and Gregg if I'm not mistaken.
... Anyway, that's the theory. When I try to use it (by using CSS), guess what? The inter-word key does not work! It still insert tatweel here and there. So, what is the problem? Just imagine a tatweel inserted between lam and alef ! That is just an example, althgouh they might be