Q:

How can be this question about VPN design either security architecture improved?

I am new to information security. According to Wikipedia NSA hacks actively on IPSec to design attacks but does it mean TLS based VPN is less flawable?
I wanted to understand comparability of both being not an expert but get downvotes.
Please share how can I improve my question.
Which VPN offers more security conceptually, OpenVPN or L2TP/IPSEC?

A:

One of the canned reasons for downvotes is "does not show any research effort". That applies here, along with your confusion of OpenVPN and the protocol it uses. 
When I googled "Openvpn ipsec", the 2 keywords your question body used (and the 2 things you wanted to compare), I got https://openvpn.net/faq/why-ssl-vpn/ as the top hit. It both answers and corrects your question. 
The rest of the hits on the page go into long explanations of the differences. 
Your new question: "is TLS-based VPN is less prone to vulnerabilities?" is a more interesting question.
We don't expect people to be experts in the areas they ask questions about, but we do expect that people have googled the keywords they use (or even the title of the question) 

