Gotcha. If it helps, a DP will contain a revision number, such as the "Harvey One Departure" (if such a thing existed, of course). Since the controller didn't include the word 'departure' or a revision number, it was not a DP, it was just normal routing.
I wouldn't count on the weather affecting your ability to get direct routing. I'm sure that controller workload, current traffic, airspace complexity and inter-facility Letters of Agreement play more of a role in that.
When in doubt, don't be afraid to say, "I'm sorry, that routing caught me off guard, can you say again slowly?"
I too, am shocked that he said "readback correct" since your version was different to his!
I recall getting an unexpected SID during my IFR training out of an airport that I'd never visited. The controller issues the clnc containing the SID...I read it back, open up the chart book, and was disappointed to see that is was "runway hdg, vectors..." Yah....LOTS of value-add from that one
Do not fear the DP! What would you rather have, a nice, pretty chart to follow out of a field...or a series of instructions that closely mimics the DP, without the benefit of referring to the pictorial representation?
The only time I would strongly consider filing NO DP is if you know that you are unable to comply with the minimum climb gradient stipulated by all the DP's from a given field. If that happens, consider drinking half of the beer you were carrying, THEN fly