With the release of the October version of the On-Premises Data Gateway (here), the SAP connector for Logic Apps now supports sending and receiving messages from SAP system configured to use non-Unicode encoding of characters such as page-code based encoding.
Also with this release, significant concurrency issues have been lifted, such that as many requests as allowed in parallel by the receiving SAP system for a given destination are now possible (in our tests the default appears to be 200 parallel requests, after which the receiving SAP system will fail the excess requests).
Upcoming and currently in internal testing is the support of table parameters for RFCs. While this kind of parameter direction is obsolete and changing kind should be used instead going forward, legacy RFCs whether out of the box or custom still sometimes use the tables parameters (e.g. BAPI_FLCUST_GETLIST). Note that this is not the same as SAP's hierarchical table types, which is not supported by our SAP connector.