Sub admins creating sub sites

Lets take the following scenario:

The site collection administrator (SCA) creates a new site "Sub Site 2" for a new team in the company. SCA wants to give the team's access to "Sub Site 2" only and permit them to administrate their site as they wish.
To do so SCA breaks the inheritance between the root site and "sub site 2", then he gives full control to the team at "sub site 2" level. The team can now access the site with no problem. The team has no access to the root site nor "Sub Site 1".

Now here is the trouble: the team need to create "Sub Site 2.1" but they get an Access Denied when trying to create the site, though they have "Full Control".
The reason is that the team can not access the masterpage gallery that is located at the root of the site collection. (http://[sitecolletion root url]/_catalogs/masterpage/)

To correct this SCA has two solutions:
- give at least "Read" permission to the root site for the team
- If the above solution is politicaly not possible SCA can give at least "Read" permission to the master page gallery only

This permission problem is almost similar with the List Template Gallery and Site Template Gallery.