The ways I see it, in a x-wind condition, a landing will require a side-slip into wind if one is to avoid side-loading the landing gear. It therefore becomes simply a choice regarding when one introduces this slip angle - during the final approach ("wing down method") or during the flare ("crab method"). I would therefore suggest that a crabbed approach with a flare that aligns the aircraft with the runway, with opposite aileron to maintain wings level is only a partial solution. Any X-wind condition will then blow the aircraft downwind, creating side-load at touch down. Lowering the into wind wing, and side slipping against the relative airflow would be the only way to maintain the aircraft trajectory parallel to the runway axis. So we find ourselves in a condition that is essentially the same as our "wing down" approach.
In the real world, of course, the more mass an aircraft possesses, the less it will be influenced by that momentary crosswind during the flare. Thus less upwind wing down will be required, so long as a touchdown follows promptly. In a lighter aircraft it becomes more of an issue because the xwong component at flare time will have more of an effect.
I appreciate that I'm looking at this rather academically, and absolutely eliminating gear side loading may not be necessarym- it is simply a case of controlling it within readable levels.
The 737 has been mentioned about its ability to withstand side loaded landings with a crab angle still present. I seem to remember being told that this was as a result of its inability to lower the upwind wing sufficiently without banging the new high-bypass engines fitted to the 300 onwards whilst still maintaining the rather squat landing gear.
I suppose my point is that, whilst this topic seems to come up with some regularity, the two approaches are not that dissimilar, and ought to result in the same outcome - a landing in the slipped condition. I would also suggest that the phrase 'maintaining into wind aileron to stay wings level' is not enough. Academically speaking, it would still result in a side loaded landing, and the object of de-crabbing in the first place was to avoid that.
2 cents etc..