Well, distributed queries, even more distributed transactions, often causes pain, so there is all reason to avoid them if you can. But if your developers have painted them so much into a corner that chaning from OPENROWSET to OPENQUERY is expensive, your prospects are bleak, since not using distributed queries at all, means a radical change in application architecture.

The problem in your case is that are using a provider that not very many here uses, and therefore it is difficult to help you. Maybe you should open a case with Microsoft. Or with IBM, if the problem is with the OLE OB provider.