Redacting Trackless Step

Hello, again. I have yet another conundrum which may, simply be me being overly cautious.

One of my players is building a device that unwittingly mimics Trackless Step.

Going over the device, I realized that Trackless Step just doesn't work out right. It starts off with a non-existent Base 4 and just goes south from there. It appears to me to be a legacy spell that they simply took the 4th edition 10th level and backed out the base from there. In 4e, it had R: Per/Touch, D: Spec (it lasted until you came to a stop), T: Ind. Now, it has R: Touch, D: Conc, T: Ind.

I'm thinking that the base should actually be 2 ("Control or move dirt in a slightly unnatural fashion") or possibly 3 ("Control or move dirt in a very unnatural fashion"). Adding +1 for Touch and +1 for Concentration would make the "correct" spell level 4 (or possibly 5). I'm leaning toward Base 2, but could be convinced it's 3 with a minimum of effort. But I wanted to see what you guys thought before I house-rule the change (and thereby set a precedent for any other "broken" spells out there...I thought I had seen a list of them on here last night, but now I I can't find it).

tl;dr: Should Trackless Step be a 4th (or possibly 5th) level spell instead of 10th?

We also noticed the same problem. We have three versions of the spell.

The simplest one is level 4: Base 2 (slightly unnatural),+1 Touch, +1 Concentration. This only affects dirt, mud and such.

To affect stony ground as well (you do not leave tracks on big rocks, but you do when walking on pebbled riverbeds and the like) it's +1 magnitude.

To affect tracks on grassy/wooded terrain, it's a Herbam requisite that adds +1 magnitude.