The obvious issues are, transactions breaking the wallet if the transaction is over 2 billion, and coin supply being misreported.
The tweaking issues could be the reward structure and the current coin supply.
In regards to the obvious:
The 2 billion limit issue is because the wallet fails to reject such transactions, so far we have developed a fix for the qt wallet,
whilst the daemon version still must be worked on further.
The coin supply issue is to do with a integer overflow where the value is too large for the coded integer type, so we are looking at converting the integer type to another that is capable to handle the large values.
This issue is particularly important because the way things are going the same issue is possible to occur with individual staking transactions .. if the transaction were old enough.
It's also possible that by the time our over all changes take effect, the coin supply will have become large enough to break the next largest integer type.
As to the tweaking issues:
There will be a hard fork coming,
this fork looks to include such as a gradual reduction in % returns, current discussion is with keeping 1200% for the next 3 months, 600% for 3 months, 300% for 3 months, then switching to a fixed reward - the value of this fixed reward will be determined to maintain a healthy reward structure for hodling and to keep long term inflation down.
Also an increase in PoW rewards to encourage mining participation.
There will be a vote for final POW/POS rewards.
The fork will also include an increase in the value of possible transactions, at the moment all transactions are limited to a theoretical maximum of 2 billion coins, with a 12 trillion coin supply, raising this 2 billion limit seems a useful thing to happen.
The fork will not address the current coin supply, but there are plans to create a new Masternode Currency, this will be attainable through swapping/purchasing with SHNDS, with the coins being burnt.
Other things in progress are updated graphics, updated code base,
Acheivments so far include:
An updated graphic (we still need some more variations to fully update the qt wallet),
numerous seeders which are now hard coded to help with network connections,
various mining pools,