The Ortofon 30 stylus is a much better stylus than the one the Sumiko Pearl has. Stylus 30 is nude (=all diamond) fine line, the Pearl has a bonded (=not all diamond, just the tip) elliptical stylus.
Some 10 years ago I had a Concorde Pro with an Ortofon 20 needle (nude elliptical stylus) in the SL-1900 in my students dorm, while I used an Ortofon Super OM 30 in my SL-1200 at my parents' place. I liked it a lot, until I switched to MC cartridges on the 1200 which moved the Super OM to the 1900 (now owned by my dad ).
Reading your preferences for "fairly fat bass, not boomy though, nice and smooth mid/top, not lean, and not too clinical" I think upgrading your Concorde DJ with a 30 stylus, or in fact any Ortofon cartridge, will suit you fine . Upgrading to a Super OM body will indeed give you more refinement, but I'm not sure weather they're still available. You could also go for a newer Ortofon 2M blue cartridge (nude elliptical stylus) which costs less than a single 30 stylus or a Ortofon 2M bronze cartridge (nude fine line, basically the same as the 30 needle) which is a bit more expensive then the 30 stylus, but also a bit better then the former Super OM 30. All these will be a significant upgrade to the Concorde body.
To put in my two pennies worth
Turntable Technics SL-1210mk2, Origin Live modified OL1 tonearm, Van Den Hul rewire, LDA/MCRU Step 2 PSU, Ianmac bearing, Isonoes, Achromat, Clearaudio Twister
Cartridge Audio Technica AT33PTG II
Tape Technics RS-AZ6
SACD Sony SCD-XB790QS
Ampification Accuphase E-205
Speakers Dali Ikon 6 Special Edition
Sub REL Strata II
Cables Van Den Hul: MCS-150M and D-502 Hybrid (Tonearm), Integration Hybrid (SACD, Tape), CS-122 Hybrid (Speakers), The Second (currently unused). Canare: 4S8 (Sub)