2. It is beyond belief that validity of a block could be decided by such implementation specific matters like BerkeleyDB record locking.
And, of course, there is no specification of what is a valid block. The code is the specification? So make no changes to the code and we won't have forks?
Please take the code at some point and write the specification of what is a valid block. Then change the code as you like and test if it's ok with the specs.
Also you may find out that the block validity rules are too weird and could refactor them better.
As Mike Hearn says, money could be lost here.
Specifications aren't magic; they're just words on paper. I can put anything into a specification, but it doesn't magically make code actually follow the spec. I can also take the specification and write tests, but again, the tests don't magically make the code follow the specification.
Before commenting further on the topic you need to read the Bitcoin sourcecode yourself. If you can't read it, you have no business commenting on software development anyway. If you can, you'll find that while it isn't perfect and could use some refactorings, all in all understanding the intent of the different parts is fairly easy and thus the code itself acts as a perfectly good specification.