This idea comes from Rolemaster. Back in the edition I played, you did three levels worth of point spending at character generation:
You only received the first two, but you had to pre-map your spending for level 2. At level 2, you'd get the level 2 improvements (and roll for stat increases) and pick those for level 3. There was even an optional rule for half-levels, so halfway between 1 and 2 you'd get part of your improvements.
Here is how you can implement this is GURPS, especially with an eye to DF.
Pre-choosing Improvements. Instead of spending earned XP, you must choose where they will go before you earn them. Each session you must designate where your next 10 points are going after they are earned. You may buy advantages, lenses, or other multi-point purchases on installment. However, once points are dedicated to those advantages, lenses, etc. they may not be retracted. As points are earned and expended, you must replace the missing points in the pool.
For example, Honus dedicates his next 10 points as follows: +1 to Flail (4 points), +1 to Survival (2 points), and 4 points towards raising ST. He earns 5 points, and puts them in Flail and 1 point towards ST. He can now choose where to dedicate 5 more points, but still has 3 points dedicated toward ST and 2 towards improving Survival. He can continue to skip them as long as he wants, but he cannot change them without explicit GM approval.
Why do this? - Basically, the idea is to force you to plan ahead, and not just react to the last session's revealed needs. You also get the "training" effect, in that you know what the PCs are working on learning. It has a nice built-in effect of wizards being in-process of learning spells, clerics praying for new spells for more than "between sessions," warriors training sword or bulking up to get more ST, etc.
Did you do this already? - Yes, sort of, with the "Slow and Steady Experience Spending" article way back in an earlier incarnation of Pyramid magazine. But it wasn't quite this implementation.
This would add some extra bookkeeping, but it also might add some verisimilitude and (like S&S Exp. Spending) encourage people to aim for, and save for, long term improvements.