I'm looking for a more detail and a larger soundstage with new equipment. The Pioneer isn't bad, but it'd pretty dated
Your not going to get a large sound stage from small bookshelf speakers. Puny speakers gets you puny sound.
A big sound requires much bigger and very well designed and crafted speakers, and a decent room to top it off.
There really is little difference in phono stages as a rule. The RIAA correction circuit is a pretty simple circuit, and there are a lot of over priced con jobs concerning phono preamps.
I think you will not get significant improvement changing your amplification.
When you do get bigger speakers, then the issue is buying a reliable quality amp, that has enough power reserve to power your speakers.
When all is said and done, your speakers and room will at least determine 99% of the quality you get from your rig.
Very few integrated amps, have the power to produce realistic concert hall sound levels. Creek would essentially be the one exception in that regard.
In most cases a separate power amp, or amps are required to get realistic concert hall sound pressure levels of large musical forces..
Good bookshelf speakers can do a good job of chamber/recital concerts and that is about their limit.