VPC peering connection are limited on the number active and pending VPC peering connections that you can have per VPC.
VPC peering does not support transitive peering relationships. In a VPC peering connection, the VPC does not have access to any other VPCs that the peer VPC may be peered with even if established entirely within your own AWS account
VPC peering does not support Edge to Edge Routing Through a Gateway or Private Connection
In a VPC peering connection, the VPC does not have access to any other connection that the peer VPC may have and vice versa. Connections that the peer VPC can include
A VPN connection or an AWS Direct Connect connection to a corporate network
An Internet connection through an Internet gateway
An Internet connection in a private subnet through a NAT device
A ClassicLink connection to an EC2-Classic instance
A VPC endpoint to an AWS service; for example, an endpoint to S3.
Only one VPC peering connection can be established between the same two VPCs at the same time
Maximum Transmission Unit (MTU) across a VPC peering connection is 1500 bytes.
A placement group can span peered VPCs that are in the same region; however, you do not get full-bisection bandwidth between instances in peered VPCs
Any tags created for the VPC peering connection are only applied in the account or region in which they were created
Unicast reverse path forwarding in VPC peering connections is not supported
Instance's public DNS hostname does not resolve to its private IP address across peered VPCs.
Circa July 2016, Instance's Public DNS can now be resolved to its private IP address across peered VPCs
VPC Peering Architecture
VPC Peering can be applied to create shared services or perform authentication with an on-premises instance
This would help creating a single point of contact, as well limiting the VPN connections to a single account or VPC