Just adding to your thought, all Goodell did was try and avoid a scenario like 2008 (punishment for 2007 spygate) where we were able to keep the pick from SF and still pick in the top 10 selections. He may have taken away OUR first rounder, but Goodell cannot take away our ability to make trades.
As you've mentioned, if N.England were scheduled to pick at say, #30 this year, they could easily trade someone for the 26th, 27th, 28th (etc) pick and really not lose that much value at all. Or in a best case scenario, they could simply trade for the 29th pick, where they'd only lose one spot. It just means that we pick at 30 no matter what, that's all.
Obviously, the choice to pick at #30 is just for example, as we all hope that it would be #32, but the point is that no matter who we traded for this hypothetical first round pick, it would automatically defer to where our original pick was supposed to be based on how the year plays out.