I for sure would not recommend a 28 for anything bigger than doves for anyone other than an SEASONED EXPERT wingshooter, and with lead shot! Steel shot is anemic at best in a 20 GA, let alone in a 28 GA.
Not all non-tox is steel, of course.
Can't quite buy the "seasoned expert" for the 28.
That is often leveled for the 410, which, imo, is never a game load...even for the quail, woodcock and doves where it is often advised and works well....but, that is just me.
The 28 is in a somewhat different league and while I think it a mistake as a general pheasant load for anyone, many do use it successfully and, as I mentioned, they often have a good dog that tends to even out memories a mite.
The 28 is also often chosen for recoil reduction, which may or may not exist to a practical extent dependent upon gun and load or, some choose it out of boredom or even those Joneses.
Choice is nice.
Soft birds larger than dove, like the ruffed grouse, do drop for the 28 gauge in anyone's hands pretty easily within 30 heavy yards....but, again, the kicker is whether the bird is head up rather than head down when pocketed for me....not the pocketing, never the pocketing.
Odds on with a 28....head will be up on ruffed grouse and larger.
The 28 has limits like any gauge and shot selection is not the only determiner of those limits.
Work within them, cross your fingers and Bob's your uncle.
Expert, imo, does not matter with any gauge or load...experience does.
The two seldom dwell together other than on message boards.
Experience w/o ego normally manages to choose a gauge for the day which has the widest chance of ethically touching any gamebird.
That is also nice.