Thank you both
Farpafraf and
Alert to Sounds for your input - I ended up keeping it, mainly because of a
meeeh that's good enough factor. For future reference (as it may seem counterintuitive) 31 HP / 18 S Def Primal Kyogre has approximately the same (if not better) special bulk than a 25 HP / 25 S Def one.
Calcs for the 31 HP /18 S Def one:
252 SpA Choice Specs Palkia Draco Meteor vs. 4 HP / 0 SpD Primal Kyogre: 244-288 (71.3 - 84.2%)
252+ SpA Choice Specs Dialga Thunder vs. 4 HP / 0 SpD Primal Kyogre: 302-356 (88.3 - 104%)
+1(Soul Dew) 252 SpA Latios Thunder vs. 4 HP / 0 SpD Primal Kyogre: 248-292 (72.5 - 85.3%)
Calcs for the 25 HP /25 S Def one:
252 SpA Choice Specs Palkia Draco Meteor vs. 4 HP / 0 SpD Primal Kyogre: 238-282 (70.8 - 83.9%)
252+ SpA Choice Specs Dialga Thunder vs. 4 HP / 0 SpD Primal Kyogre: 296-350 (88 - 104.1%)
+1(Soul Dew) 252 SpA Latios Thunder vs. 4 HP / 0 SpD Primal Kyogre: 244-288 (72.6 - 85.7%)
So if you would consider a 24-25/24-25 one when you are SRing, definitely go for a 31/18-19 one, as it keeps the same special bulk while having a better physical bulk because of the HP IVs being perfect.