Attached is a working implementation of the idea.

So, in GTD each 'next action' is supposed to be an actual doable
thing to further the project it is associated with.

When creating next actions or project headlines there is sometimes
a tendency to use a heading that is a bit vague/undoable. This is
usually a sign that the task the headline represents needs more
thinking about and will probably need more than one next action or
spawn another project.

org-action-verbs was created to use a list of GTD 'action verbs' to
diagnose non-functional next action and project headlines. It searches
for headlines of a specific TODO type and checks to see if the first
word in the headline is specified as an action verb for that TODO
type. If not, then it highlights that first non actionable word.

Its a bit like flyspell mode but for checking doable org headlines.

To use put the following in your .emacs:
(require 'org-action-verbs)

To change the default TODO Type->Action Verb table you can set
'org-action-todo-verbs'. Below is an example. The first checks for the
right spaceship name associated with the 'SPACESHIP' TODO type, and
the right colour for the 'COLOR' and 'COLOUR' TODO types.

- note the Action verbs are case sensitive.

(setq org-action-todo-verbs
   '(
     (("SPACESHIP") . ("Challenger" "Voyager" "Enterprise" "Nostromo"
"Apollo" ))
     (("COLOUR" "COLOR") . ("Red" "Yellow" "Green" "Aquamarine" "Blue" "Black"))
     )

The current default mappings are based on David Allen's GTD verb list:

Verbs for the TODO types "TODO" and "NEXT" ->

Address Ask Avoid Buy Change Clarify Collect Commend
Confront Consider Create Decide Defer Develop Discard
Do Again Download Enter File Follow Up Hire Improve
Increase Inform Inquire Enquire Maintain Measure Monitor
Order Paint Phone Prioritize Prioritise Purchase
Question Reduce Remember Repair Reply Report Research
Resolve Review Schedule Sell Send Service Specify
Start Stop Suggest Tidy Train Update Upgrade Write

Verbs for the TODO type "PROJECT" ->
Finalize Finalise Resolve Handle Look-Into Submit Maximize Maximise
Organize Organise Design Complete Ensure Research Roll-Out Update
Install Implement Set-Up

Enjoy,

Tim.