vpn – Will pulling firewall from router into separate device in front of the router increase security?

To secure a router available at a public static IP address from various vulnerabilities discovered and exploited from time to time (or other examples), would it help to separate its firewall and/or VPN capabilities into dedicated device put in the front of the router?

(At the first sight, it appears safer – since to gain access, two devices must be exploited instead of one.)

Original:

   ISP --------------------------------> (Router w/Firewall)

Is the following more secure?

   ISP ---------> (Firewall) ----------> (Router w/Firewall)

(or maybe even with original firewall disabled)

   ISP ---------> (Firewall) ----------> (Router with disabled Firewall)