Yes, it is true that bitcoin needs to improve. Bitcoin needs to be renewed with renewable technology innovations. First, bitcoin needs to increase its transaction speed. It is very important to keep bitcoin remains the society's choice for transactions. Now, bitcoin takes 10 minutes transaction time. That's a long enough time in a long time that bitcoin only able to do 6-7 transactions. Now, altcoin is present that offers transaction speed in just a few seconds. This certainly threatens the existence of bitcoin. Bitcoin has a small block size, about 1 MB. This includes a very small size so bitcoin should increase the block size if bitcoin still wants to be the community's choice. Other altcoins are also available that offer a large block size so this becomes a warning for bitcoin. The last, bitcoin needs to increase traffic transactions to remain stable when hard fork occurs. That's my bit of advice for bitcoin.
I think Privacy is another issue, but the upgrade also goes in to take care of it as well. Besides I do not see much need for improvement, it's not like we need to make Bitcoin great again
I hope you are joking because there is much we can fix right now. First of all we can improve the speed and cost at which we transact because they are not up to par and with LN coming that will change easily.