I have always given BG1 Fixpack as much importance as the BG2 Fixpack has. Idobek has already done a good part of the job. The goal would be to have a team like the BG2 Fixpack's team work on it.
I am no modder but I got to know Dudleyville's fixes so I can help with a little experience in there to perhaps individuate those fixes that should be moved to OBC.
Also, it's a must to make it EasyTuTu/BGT compatible as well, just like Miloch said. Problems with EasyTuTu is that it comes "prepatched" as MacReady's intention is to make EasyTuTu as userfriendly as possible. At today, if I am not mistaken, BG2 Fixpack's corrections, despite reaching a pretty stable status, cannot be had on EasyTuTu which is very rigid in its structure. On the other hand, a BG1 Fixpack would not work on BGT for another reason (Ascension64 has coded his own BG1's fixes - very limited - in BGT but that doesn't mean that future fixes, if well documented, can't be included)...