I fear a central repository of all CT packages for usage in Lazarus is a very bad idea and will end up in a terrible mess. I am not talking of these packages which are unique to CT, but of that vast majority which are just copies of Laz packages. Units and packages are renamed, but the classes are named like their Laz counterparts. There is nothing to prevent a user from installing a CT package and the corresponding Laz package simultaneously: now each class of these packages will be duplicate and, therefore, the package will not be functional any more, not sure - but maybe even Lazarus will stop working.
Moreover, these CT packages which duplicate Laz packages are less maintained than the Laz packages. Looking into the CT forum I see almost no activity, compared to forum and bugtracker here, and bug reports are usually commented as "we will look into this issue", and then, when Laz has fixed the issue, the fix will appear in the next CT version.
ct2laz is a great tool to make those CT packages available which don't have a Laz counterpart. But this is a tool for somebody who knows what he is doing. A repository of ready-to-use CT package will cause more trouble than benefits. Instead of this I'd pick those CT-only packages, convert them to Laz and distribute them in OPM. An example is the package "astronomy" which is now in OPM, but originally was a CT-only package.
But - this must be clear: All these packages will not be maintained, and I see the future that OPM will end up like CCR: initially lots of enthusiasm, but a few years later, when the excitment has gone, it will just accumulate dead code. What if FPC introduces another code-breaking feature? Or Laz moves functions to other units again? Or code marked as deprecated is finally removed? These things usually are easily fixed, but somebody must do it. Who? Who will take care of the more than hundred packages in OPM when this happens? With CT in there it will be even worse! (well, I am very pessimistic today...)