you shouldn't be too harsh though when devs, and companies in general, spend resources on eye-candy.
a good AI, like GalCiv's for example, is guaranteed to not only ensure replayability, but attract interest on its own. But therein lies a problem, ie. it can only attract players (ie. consumers) who have an innate interest in strategy and/or familiar with the genre. this essentially means that the "consumers" it attracts are the "connoisseurs" and not the "casuals" (the latter who, let's be honest, outnumber the former the same way "elites" are outnumbered by "rank-and-file")
a good UI, however, is guaranteed to attract the passing-glance and tempt the "casual" into trying the game out in the first place. it also assists in the replayability aspect by making the game more relaxing, ie. less eye-straining in comparison to contemporaries. Total War, to use your example, may be a relative let-down in the AI department, but the average-player would rarely notice the difference but would more easily notice the UI-difference, which Total War scores high on.
It's ultimately an EU-ish slider between UI-focus = more casuals/less depth and AI-focus = more connoisseurs/less accessibility. And as a business, they need to decide how to stay profitable and expand their market without damaging their existing support.
As a personal example, I was a Total War fan myself, having gotten into the strategy genre via Rome Total War. I've been familiar with Paradox's other games for some time now, but what made the slide easier for me was EU3: Divine Wind, whose map was aesthetically pleasing enough that I could tolerate it (it does have much less detail than TW games) enough to engross myself into the mechanics and thus actually care about AI in the first place (hell, now I'm even a modder :laugh: )
besides, the article itself discusses how AI-coding is mostly now limited to the amount of man-hours spent in coding and optimising, and only significant computational breakthroughs can further improve AI. besides, just how accurate is the player's conception of the AI anyway? what may seem like a brilliant move of the AI by one player might be seen by another player as a retarded and suicidal action, given the exact same scenario.
at the same time, improving graphics is only limited by the hardware speed available, which regularly increases as time goes on. it's obvious that graphics would advance further and faster than the AI. and, unlike the AI, it's easier to be more objective about how "better" the previous iteration is in comparison to the former
I'd personally liken it to neuro-surgery and dermatology, as the simile kind of works :laugh: