If it was mine I would re-power when in good condition. Some of the ride-ons coming out now for the homeowner are not as good as the older stuff. Later models did used the 310000 series Briggs OHV.
I got an older 2005 Bolens (MTD) that out cuts most of the newer equipment customers bring in for repairs here. I have had mowers in here that couldn't even cut lightly over grown lawns as they were so under powered. This the case for 2009 Bolens model the engine is about 2 hp short as it tries to stall out when cutting grass. No way it would cut that 12+ inch grass that 05 does. Main difference between the two is the 05 has 15.5 hp with 38" cut and the 09 has 16.5 Hp with 42" cut.
Yes,
One of my main concerns was that is was badly re-engined and then, underpowered. With the deck drive method and the weight I'd think that the the original 15.5hp was good for a lawn only and offered just sufficient power.
If I keep it then a 18-19hp powrplants and some tuning would be the only options. A bit more HP won't hurt. I won't go to a 25 or similar as they'll overstress the drive train to the point of premature failure with no real benefit.
Just thinking out loud at this point. It still may be only worth it's scrap value.
