Hmmm. I think this comes down to a general philosophical question of genome design having to do with sysvar space sparsity and how conditionals are expressed/evolved in the DNA.
In general, if the space of valid sysvar values is sparse, then as you say, bots can evolve code where values are stored each cycle and the result of some calculation governing the stored value is essentiallly the conditional. Nothing happens until they hit upon the right magic value, or a value that is in the small range relative to the space of all possible values.
If on the other hand, storing just about any value into a sysvar reuslts in some morphological action, then bots would need to evolve conditional logic which dictates whether the store occurs or not if they did not want it to happen every cycle.
Using your example, it's the difference between
*.robage 1365 sub .repro store
*.robage 1365 >
(any number) .repro store
Personally, I prefer the latter design approach for several reasons:
1) I think it results in faster evolution. When the space of possible sysvar values that result in morphological action is not sparse, a given string of DNA has a higher probability of doing something which selection can then favor or not favor. Action evolves first, then conditional action.
2) I think it results in a milder slope in the fitness landscape leading towards stable traits and strategies. For example, in the first approach, incremenenting or decrementing through sysvar values as in the example above as a means of hitting upon a value which does something would probably be a common approach bots would evolve. Makes sense for evolution to just walk through every value to find the ones that work, right? But because the space is spares and the range of values that do something contigious, the result is that nothing happens for a while and then suddenly a lot happens. In the example above, it reproduces every cycle after beginning its 1365th cycle of life, giving each offspring a differnet nrg percentage. I would claim (without evidence) that it is harder (I.e. that the genetic distance is further, requiring more subsequent mutations) to go from this genome to one where a specific nrg percentage is used (or a number of other 'stable' strategies) than it would be were the sysvar space non-sparse and the conditional evolved as a conditional for performing the store, not the value.
Try the mental excercise of mutating different single base pairs in both genes above I.e. change a number, change a sign, change a operator, etc. Which gene is 1 base pair away from a larger number of interesting reproduction strategies? I would claim the second.
Granted I am arguing from opinion without data, but there's my argument. I just prefer a dense sysvar value space.