There’s no doubt that the Starter Kit is the best value and variety of parts for the money. To reconstruct it, I think you’d need:
Hardware & Metal Kit : $80
Gear Kit: $13 (but call it $10, since you don’t get the 84-tooth gears)
Wheel Kit: $30
Motors & Servo: $80
Misc. doodads, like PWM cable, wrenches, etc. ~ $20
That’s ~$500 of stuff for $300, and I don’t think any of the other bundles give you that much savings
But I must say that I am not a fan of the Starter Kit as a “Starter Kit”, i.e., first-time kit for Vex newbies. My son and 3 friends (all FLL graduates in high school) each acquired the Starter Kit shortly after its release. After building the Squarebot, they couldn’t envision anything else they wanted to build. The metal was too long, and no one wanted to cut anything, for fear of ruining it. Offers of joint build sessions (to combine parts) were turned down. Those 4 Starter Kits sat in closets for nearly a year.
What turned things around for us? The Radio Shack 50% off sale. We stocked up on metal, gears, and the programming kit. I deliberately cut some metal to stock sizes, and reassured my son that we could purchase more if he ran out. He started to tinker, realized that Vex could be enjoyed, and we decided to buy TWO Starter Kits for a school team (intended for one robot, not 2). We urged the other 3 members to stock up on parts to make their Starter Kits more fun. They did not, and those 3 kits still sit in closets.
After 3 years of Vexing, I can finally say that we have found every piece in the Starter Kit to be useful (except, perhaps, the plethora of 1/4" screws), but it took 3 years to learn to use all the parts. For the sake of veterans like us looking for a good value, I would love to have the Starter Kit kept in circulation, but perhaps it ought to be renamed something like the “Builders’ Bonanza kit”. Its optimal audience is definitely not “Starters”.
After watching what my son and his friends initially found useful in the Starter Kit, I noticed that the parts that got used were gears, wheels, axles, and structural metal that didn’t need to be cut. I definitely think the Protobot kit is a step in the right direction for that audience, but I agree that a little more metal would go a long way. More 4" axles (why only 1?), longer axles (12"), gussets, a couple more small (5X15) plates, and a couple more chassis bumpers would give much more variety to the kit.