It is not my intention to sound flippant. But the question whether wolfpacks were a good strategy has to be answered in two parts.

When wolf packs worked, they worked well
When wolf packs did not work, they stunk.

If three or more submarines can manage to all meet up with a juicy convoy, wolf pack tactics are a good tactic.

However, if three or more submarines manage to meet up and there is no juicy convoy, you have a tactical failure.

An argument could be made that it would be better to spread out the three submarines to cover different areas, rather than putting our the submersible eggs in one location.

One of the key aspects of wolfpacks is coordination. Coordination requires communication and that was the weakness of the wolfpack tactic.
Submarines work best when there is the element of surprise. Transmitting communications can remove this advantage. If a convoy is aware of the presence of submarines it can take protective actions, call for focused air support (if in range), request surface protective support. All these make it harder for the submarines to sink the ships.

Which would be better
1. Sinking four ships in a convoy
2. Not sinking 20 ships in a convoy because they were alerted to your presence?

Another key aspect of wolfpack is cooperation. In this context I mean the cooperation of the convoy. The convoy has to be located, tracked, and must appear at the wolfpack spot at the right time for the wolfpack tactic to work.
Many factors can influence the track of a convoy. Weather, mechanical problems, navigation errors are just a few factors that can affect a convoy being “there” when it should be “here”.

If the submarine forces have a good way of detecting, identifying, tracking convoys, Wolfpack tactics are probably a good idea. Miss one convoy and not only does that convoy escape, but the other two convoys that could have been intercepted if the submarines had not been in a wolfpack also get away.
BdU’s tactic of having one U-boat shadow the convoy while the rest of the wolfpack assembles ahead was a method to help this problem. However, even if the codes are not broken, the communications from the U-boat alert the convoy (either by itself or by being informed by shore/other units) that it is being shadowed. This gives the convoy time to implement protective actions as listed previously.

Add in the ability to decode the message so that the com internals can be read, only makes the wolfpack tactic more difficult to implement.
The final key aspect of wolfpack tactics I would like to address is the number of submarines. The more submarines you have, the more attractive wolfpack tactics will be from a resource point of view. If BdU had hundreds of U-boats available, wolfpack tactics would work better. However, if BdU has a hard time keeping a dozen or so U-boats on patrol, it makes wolfpack tactics much more expensive from a resource viewpoint.

Spending 20% of your available U-boats to form one wolfpack on the chance (which may be good or not so good) of attacking one convoy may not be an efficient expenditure of your U-boat allowance. It might be better to deploy those 20% into three separate locations (choke points) and damage three convoys.
One advantage of NOT having wolfpacks is that by potentially threatening convoys in multiple areas (because the U-boats are disbursed) is that the enemy has to spread his protective forces over more of an area, because the non-wolfpack U-boats can operate under more (but not absolute) radio silence.
So wolfpack tactics have advantages. But there are other factors that influence the effectiveness of wolfpack tactics and not all of them are under the control of the attacking side.

As for many historical questions about was xxx a good idea, the answer is often: Yes, no, and maybe.