Monero will stick to its core competency of being safe money for everyone. It will incorporate improvements to improve decentralization, security, privacy, and efficiency.
Currently, Monero transactions are relatively large at about 13kB. Research on bulletproofs, a more efficient range proof for RingCT, is expected to reduce transaction size (and fees) by 80-90%. The code is live on testnet and is undergoing peer review.
Monero has a minimum ringsize of 5, meaning each transaction must include at least 4 decoys in its ring signature. Research into RTRS RingCT setups will allow for a more efficient use of decoys, meaning it can be increased to 32 with no performance or efficiency loss. Many community members advocate for a single mandatory minimum ringsize instead of a minimum, since some users reduce their privacy by increasing this number. Research in RTRS RingCT is still relatively new.
Side chains will come to Monero. These will be optional networks (typically prioritizing efficiency) that will work (as the name implies) on the side of the normal chain. These sidechains will allow for significant flexibility.
