Bear in mind that a piston is the stated diameter......at the gauge point. It isn't that big anywhere else. The skirt is tapered from the guage point to below the oil ring, then the diameter steps down about .030/.040, then the top land steps down another .040 (if it's over .300). So a piston that is 4.386 a the gauge point is around 4.356 at the ring lands....allowing it to rock all the more.It is my understanding that the longevity issue stems from how far the piston comes out of the bore at bottom dead center when using a 4.5" stroke configuration with a production block such as in the 545/557. What seems to happen is, with the piston comes so far out of the bore @ BDC it will rock in the bore and cease to be square with the cylinder. When this happens the bottom of the cylinder wall acts like scraper and scuffs the piston skirt causing excessive wear to the skirt. Wear that wouldn't normally happen or be as severe with the 4.3" stroke used in the 521/532 stroker confuguration as the piston stays a bit farther up in the bore @ BDC. Now this will tend to be compounded when using a piston, like a 2618 forging that requires more clearance and looser fit in the bore. Add to that even more clearance during cold starts and for nitrous and/or forced induction applicatios and it gets worse. All this leads to greatly reduced piston life which is why most engines you see built with the 4.5" stroke aren't ones that get driven all that much or they are strictly used on the track and will get torn down or changed up seasonally or at least before they fail (maybe).
This is why I dislike the 351C with a 4.000 stroke and a 6.000 rod.
As for the 4.500 Stroke....you do have room to run a longer rod.