I don't know. As I said, the Solo system does requires to step in and make "human" decisions. In a sense, it is "incomplete". Maybe that was a problem, as least for the beta testing version that LNLTD is still. Maybe this will be worked in later?
Those "human" decisions that might have to be made using the Solo system I would be confident represent only a minority of the instances. Regardless, from what I am hearing, I have yet to hear a negative assessment for how the Solo system simulates a respectable opponent. Any aspect of "incompleteness" in the Solo system I am sure might just apply to some rare fringe cases that doesn't invalidate how effective the system is for solitaire play. I could even imagine that perhaps it is "incomplete" because proposed rulesets may be too convoluted/complex for PLAYERS to reconcile, whereas if the same ruleset was coded, the CPU doesn't care how complex the algorithms are. The player just sees the end result ie. CPU opponent moves.
I think also the AI for the Digital game was being worked on before the Solo cards for the board game were finished and released. So there wasn't really a time when the board game Solo could be programmed into the digital game.
This definitely is interesting! I would think that the ONLY practical reason why a separate "AI system" specifically designed for a PC adaptation of a board game would be developed would be to remove any "complexity" limitations and take advantage of all the things and possibilities that can otherwise be achieved when coding in a digital medium.
A set of very complex and convoluted AI rules and algorithms developed in computer code is of no consequence to the CPU processing the code, yet it may be too complex to otherwise express as a physical rulebook with literal rules/charts/tables/factors/die rolls etc that a human player would otherwise need to understand and administer manually. As mentioned, unlike humans, a CPU doesn't really care how complex and convoluted an AI algorithm is to process even for the most basic of actions.
This situation would not be so confounding if the AI system in LnLTD was clearly better and superior at simulating a human opponent than the Solo AI system in LnLT. But this clearly does not seem to be the case.
I hope LnLP chime in on this to clear up exactly what decisions (and why) have been made regarding the implementation of a separate AI system in LnLTD that by all accounts is INFERIOR to the Solo AI system of the physical game.