Even if Aiko's reclist is shorter, and appears simpler, it's still a relic of the inconsistency present in earlier reclists. Some of the ideas that were first introduced via that reclist are more fully developed in VCCV. If you follow the recommended workflow of using guideBGM in OREMO, you can record an entire VCCV voicebank very quickly, and immediately begin to use it with the provided base OTO.
Should you decide to pursue Arpasing instead, the default reclist only has some 200-odd samples compared to the 1000+ in VCCV. You can consult this guide for a complete explanation of how to create an Arpasing voicebank:
https://arpasing.tubs.moe/en/resources/vb-creation.html
This method is probably better for simple, beginner voicebanks than VCCV, if you find that reclist too daunting. Please let me know if you have any specific questions when you try it out.