Thats why I think they should add in "Hybrid" PrEs to give a place to PrEs that don't fit with just one class..Eldritch Knight require levels in both an arcane and martial class...Sacred Fist requires Monk + Cleric...Arcane Trickster requires Wizard + Rogue Mech...????? requires Rogue Mech + Arty Master Maker (this just needs to be done)....Corrupt Avenger requires Palemaster+Divine Avenger....etc.
Here's a quick example using Swiftblade (and using the Tempest Template)
Core 1: Arcane1/Martial1 Character Level 3
Core 2: Arcane2/Martial2 CL 6
Core 3: Arcane4/Martial4 CL 9
Core 4: Arcane5/Martial5 CL 12
Core 5: Arcane6/Martial6 CL 15
Core 6: Arcane7/Martial7 CL 18
Capstone: Arcane8/Martial8 CL 20
Note: This means a Arcane18/Martial2 would only have access to tier 2
The "Free Bonuses"
5 Points Spent: Gain Spring Attack
10 Points Spent: Swiftblade I, 10% Blur Effect, +1 AC, To-Hit & Reflex Save
15 Points Spent: Haste Lasts 50% Longer
20 Points Spent: Swiftblade II, 20% Blur Effect, +2 AC, To-Hit & Reflex Save, All Hits deal an extra 1d6 Untyped Damage
25 Points Spent: Haste Lasts 100% Longer & Cannot be Dispelled
30 Points Spent: Swiftblade III, 30% Blur Effect, +4 AC, To-Hit & Reflex Save, All Hits deal an extra 2d6 Untyped Damage
41 Points Spent: Perpetual Celerity - When any Haste effect is on you it lasts until Rest/Death
The PrE Tree itself would likely have a bunch of movement related things like increased run speed, immunity to knockdown, freedom of movement, balance, jump, tumble,etc.