Might I point something out?
Gestalt characters aren't (usually) overly much stronger than regular characters of similar level - they've generally just got better endurance and are more durable - they don't generally have all that much of an edge in brute power (there's exceptions, like the Druid//monk, but for the most part, they're not really stronger). Gestalt guidelines say +1 or +2 CR on what you'd otherwise be throwing at them. These Hybrids are basically taking Gestalt, and making it a +3 LA template... with PrC's taking up both "sides". It's not really noticeably stronger than regular play, and will usually be weaker (okay, the Fighter-3/Barbarian-3/Hybrid-X will be slightly stronger than most Fighters or Barbarians... but only just, and at 7th, you're getting into territory where non-casters are left behind).
Gestalt characters create much more room for optimization and synergy between abilities. This makes gestalt characters vary in power much more than normal characters. There isn't only a handful easily breakable combinations; there are many. While this variant reduces the power of gestalt character, I suggest not playing gestalt at all (at least not with players who are known to optimize) unless you're ready for some headaches and a lot of rebalancing.