Fiori with bdc togetherness

Dear SAP team,

I am planning to perform interface conversion (most of present running) to SAP Fiori Transactions.

Overall ,delving into deeper details,i find that BDC in harmony with SAP Fiori have numerous issues like

display of screens or some users have been seen struggling to cope up with bdc processes working in background.
A clarity on this side would enable me to plan my activities further ...like some module pool programs have to be converted to transactional fiori apps.

In these module pools somewhere at SAVE buttons i have used bdc codings (obviously where BAPI was not present from standard sap).

Now how to move things further .. ?