The pro of better lubrication can be achieved with full groove main bearings, so if the weakening of the crank disturbs your peace of mind, the advantage can be had in another way. But I do not think it weakens too much to the point of compromising the engine reliability in street use. It is said also that it makes more oil splash around the crank and so more oil to the cilinder walls loading the oil rings a little more, then maybe some more oil consuption. I'd not avoid using a full groove main bearings just for that. Using a better oil pump would be wise.