The original game was designed with DPs and without all those secondary skills. If no extra DPs are given, then primary skills costs should be reduced, not the other way around.
Not giving any extra DPs to round out the character will actually take away from primary skills or become cookie cutter, especially if using all the RoCoII skills and expecting the players to use them. Also encourages min/maxing
RMSS was designed for all the skills so no extra DPs needed there.
We've never had a problem with the cookie cutter PC with the given DP formula. Take the Fighter example that was used. Once the primary "bread and butter" skills are taken (weapon 1, weapon 2, armour, Body Dev, Stunned Man., etc.) there were enough DP left over to pick from the dozens of secondary skills, to give the PC unique flavor. And there is where I see the cookie cutter disappearing even more. With say 30 secondary skills to choose from... you would need to make 31 fighters before you saw a duplicate "cookie." It sounds like that you're also going under the assumption that 10 fighters also miraculously rolled the same 10 stat rolls and Stat potential rolls and have the exact same stats across the board.
Don't forget, even while it's cost prohibitive, magic skills are still an option for the fighter. We had one level 5 fighter who knew 1 spell list to level 5. He spent the 20DP at level 1 and just made a spell gain roll each time he leveled up and got lucky one time with a 96 dice roll.
Add to that, the 10 stats RM has. Those stats will also effect other skills and make the Fighter better/worse at some skills, primary and secondary. Selecting secondary skills that take advantage those good stats adds yet more variation.
As the PC levels up, there is diminishing returns on the Rank value. 5, 2, 1, 0.5 depending on the optional rule you use and Body Dev stops being useful once you reach Racial Max +CO Bonus, so no need to spend DP there. The fighter at Level 4 may decide that the 10 ranks in Weapon 2 is enough, now those DPs are freed up for more secondary skills adding even more flair to a PC.
Is the system perfect? Not for everyone. Does it have weak spots? Of course. Is it as constricting as "6 stat, 1D20, no DP" system? Nooooooooo.