Don't really think there is a right or wrong answer to the substitutions question, its all about opinion. HRK came on for Gayle, he doesn't offer the pace or spark but has scored two goals coming on as sub and showed some know-how to draw a few fouls and kill the game off in the last few minutes of injury time.
The one causing discussion, the Barry substitution, wasn't made until the 87th minute, and was a standard pack the midfield and "lets see the game out" kind of substitution. This did draw some pressure, but it was working until JRods legs went (he did some miles on Saturday) and he just could not get to Pieters who hit a peach. Burke for Barnes would have left us with three out and out attacking players on the pitch (Burke is no all rounder like Barnes). Maybe we could have left Burke up top and played JRod and HRK deeper, but I can't say I'm sure that would have been the best decision.
In conclusion, I have no conclusion as to the quality of these substitutions. Conservative? yes probably. Poor or wrong? Not sure about that.