VLS needs more diameter of sub and so more displacement. If you intend to acquire bigger submarines you can consider to put VLS on it. If we are talking about current status of our subs, torpedo tube lauched cruise missile is the only option. We can not operate so much bigger boats in our...
We don't need to be VLS on U214TN's to launch the Gezgin SLCM. You can deploy if it's diameter fits to the 533mm torpedo tubes just like Israel did it on Dolphin Class subs.