Try to make DNS SRV setup sound scarier (which it is)

We've had people who get the impression that well-known = bad,
DNS SRV = good, and who try to use DNS SRV for server delegation.

While it's true that DNS SRV can be superior for high-availability
scenarios, it's much harder to set up and comes with its own potential
downsides.

Using the well-known method is more straightforward and is enough
for almost all of us. Throwing people into the deep for no good
reason is not nice. Hopefully wording is better after this patch.

docs/howto-server-delegation.md

@@ -28,14 +28,14 @@ Server Delegation by means of a `/.well-known/matrix/server` file is the most st
 
 > Errors are recommended to be cached for up to an hour, and servers are encouraged to exponentially back off for repeated failures.
 
-If this is not a concern for you, feel free to not read ahead.
+**For most people, this is a reasonable tradeoff** given that it's easy and straightforward to set up. We recommend you stay on this path.
 
-Otherwise, you can decide to go against the default for this playbook, and instead set up [Server Delegation via a DNS SRV record (advanced)](#server-delegation-via-a-dns-srv-record-advanced).
+Otherwise, you can decide to go against the default for this playbook, and instead set up [Server Delegation via a DNS SRV record (advanced)](#server-delegation-via-a-dns-srv-record-advanced) (much more complicated).
 
 
 ## Server Delegation via a DNS SRV record (advanced)
 
-**NOTE**: doing Server Delegation via a DNS SRV record is a more advanced way to do it and is not the default for this playbook.
+**NOTE**: doing Server Delegation via a DNS SRV record is a more **advanced** way to do it and is not the default for this playbook. This is usually **much more complicated** to set up, so **we don't recommend it**. If you're not an experience sysadmi, you'd better stay away from this.
 
 As per the [Server-Server spec](https://matrix.org/docs/spec/server_server/r0.1.0.html#server-discovery), it's possible to do Server Delegation using only a SRV record (without a `/.well-known/matrix/server` file).
 
@@ -47,7 +47,7 @@ To use DNS SRV record validation, you need to:
 
 - ensure that you have a `_matrix._tcp` DNS SRV record for your base domain (`<your-domain>`) with a value of `10 0 8448 matrix.<your-domain>`
 
-- ensure that you are serving the Matrix Federation API (tcp/8448) with a certificate for `<your-domain>` (not `matrix.<your-domain>`!). See below.
+- ensure that you are serving the Matrix Federation API (tcp/8448) with a certificate for `<your-domain>` (not `matrix.<your-domain>`!). Getting this certiface to the `matrix.<your-domain>` server may be complicated. The playbook's automatic SSL obtaining/renewal flow will likely not work and you'll need to copy certificates around manually. See below.
 
 
 ### Obtaining certificates