🚀 go-pugleaf

I recently examined a close-up picture of the Space Shuttle, and I was
puzzled by some of the design features. Please excuse my ignorance but:

1) Why is the tank so blunt? Isn't the shuttle a super-sonic vehicle?
Shouldn't this be sharper, say one of theose secant ogive numbers?

2) Why is the tank so rough? Not only is the texture less than smooth,
but there are a number of grooves near the front as well.

3) The struts that hold the shuttle to the tank are apparently naked
cylenders. Shouldn't these be streamlined in some way?

4)On the side od each SRB, there is a piece of metal running lengthwise.
Is this a strap to hold the segments together? 

5) Wouldn't the SRB segments mate more reliably if the propellant grain
from an upper segment extended into the next lower segment? That way,
the propellant segments wouldn't coincide with the chamber segments and
the infamous O-rings wouldn't take as direct a blast. No? 

Just curious. Thanks much.

-Larry C.