Very little of the weight of a bike is in the frameset. IIRC, my '87 vintage Reynolds 531 frameset weighs in at 5 lbs even.
Without looking up the specifications, the weights you cite sound like they're the versions of the bikes with pretty low-end components. It all depends on your budget.
Again, without looking up the specifications - very often, when you buy a complete bike, the wheels are the lowest-end components and the upgrade where you can get the most bang for your buck. Wheels are also rotating weight, so saving weight in rims and spokes gets you much more gram for gram than saving weight in the frameset.
All that said ... the amount of weight you'll save by spending an extra $5,000 on your bike isn't likely to make much difference in your climbing ability, unless you're talking about racing at a level where that kind of investment is worth it to you. The 20-25# you're losing by switching to a road bike WILL make a difference, as will the more roadworthy geometry. Between one road bike and another, technique, fit, and cogset selection will make more difference to you than anything. Buy the bike that fits, not the lightest one you can afford; get it fitted to you well, learn how to climb on a road bike, and then upgrade your wheels if you still have money burning a hole in your pocket.