So it would mean even buying newer more powerful cards would not guarantee solving the problem, but it might alleviate it?
Exactly
I'm hoping this indicates the problem is lessened with newer cards?
Really not. Newer cards are more likely to maintain 50+ fps, which usually is the hot spot for microstuttering, but is only about pure performance. And with people using powerhouses as 295gtx for 19x12 and less or so (295gtx counts like two cards in sli), there are not many people noticing it.
Then the question would be, I suppose, would it be better to invest in one supermegacard rather than 2 in SLI
SLI is useful if you know (reviews with benchmarks on the net) you will have 50-60 min frames with a configuration similar to yours. If not, a monogpu system will be more reliable.