It's awesome that the standard is getting revisited. In my view there are four main problem areas. I think it's most important that the broken or lacking core language features be addressed! Other languages have groups continually going over these things; Common Lisp needs one too. (1) Missing or broken language features that should be added or fixed Crummy type-system (at least parameterised types please)! As Levente also brought up: also access to type inference, etc. This would allow: Efficient generic functions dispatched to inline expansions at compile time. Value semantics. More help for code walkers and transformers (what does a declare form refer to?, etc.) Limited(?) serialisation of closures. Ability to locally alias a symbol and package (2) Brokenness in the current Lisp standard Different facilities should be separated and put into different packages. Pathnames are overly complicated and do not handle symlinks well. Extensible sequences, gray streams, etc. Hash-tables should be generalised like extensible sequences allow user implementation of other datastructures. eq, eql, equal, equalp are not enough; nothing should restrict itself to these comparisons. Generally all functions like +, -, equal etc. should be overridable for user's custom types with the efficient compile-time dispatched generic function mechanism. This would allow (explicit) laziness! Possibly kill the many bizarrely named or strangely parameterised and hardly used functions like `get'. (3) Stuff all implementations provide but is not standard Unsafe machine pointers Weak pointers Details from room GC Stack frame inspection etc. (4) Libraries that basically already exist but would be useful as part of the standard cl-ppcre, local-time, osicat, cffi, etc.