That's a little too ghetto for iFixit.
The whole point of that guide is to remove the logic board so you're not messing with any of the other components while using the soldering iron. iFixit presented the safest option. I wouldn't recommend that people follow your advise (even though it sounds feasible) just because it's kinda of jerry-rigged.
If you want to take a step further, you could technically just follow the soldering steps without removing the board. I do NOT recommend that. There's no reason to use heat shrink tubing at all.