On a first reading I tended to agree with some
of your arguments. However:

> When choosing a crypto package, there are a few points to consider:
> [...]
> - the maintenance of the package
> Flaws are being discovered everyday. It is better to use a crypto
package
> which is widely used, tested and maintained.
> [...]
> I think the last and worst thing to do is to re-implement some crypto
from
> scratch.

But what do you think of:

"When choosing an operating system, there are a few points to consider:
[...]
- the maintenance of the OS
Flaws are being discovered everyday. It is better to use an OS
which is widely used, tested and maintained.
[...]
I think the last and worst thing to do is to re-implement some OS from
scratch."

More seriously, perhaps, a well-known source of flaws is complexity.
Expressing algorithms in Ocaml is often (much) less complex than 
in C...

I cannot be more specific in this case, because I did not examine
the implementations. However, as you say yourself:

> When choosing a crypto package, there are a few points to consider:
> 
> - the people who implement the package

Regards,
  Jean-Francois