Been looking for this thread!
Many ideas have been suggested over the previous pages, including a few myself.
With the new look Sky News now on air, a few revised thoughts:

ITV News needs to get it's niche right. It has a strong regional network, and even without the introduction of regional bulletins, it can use the strength of it's regional links much better.

It's weak point is undoubtably international news. It's an area that needs improvement, but I wouldn't go as far as suggesting a world news bulletin until they have the network of correspondants to do it justice.

With Sky's appointment to view schedule they use their flagship, though not nationaly recognisable, names to good affect. ITV have some big names on the channel throughout the day, but they are poorly scheduled, and we now seem to be back to something similar as before the 2004 relaunch, with alot of random presenters.
Andrew Harvey, Alistair Stewart, Leyla Deybelge and Felicity Barr are all names the schedule can be built around - but obviously it needs more promotion on ITV1 - even if not during the Corrie commercials, during the ad breaks with no ads!

Though the overnight service is poor, it's not the first priority. In my opinion, the weak points of the schedule are in the hour before the ITV1 bulletins when the News Channel switches studio - and presenter - mid-bulletin so the ITV1 team can prepare.

And finally, of course the situation on Freeview is ridiculous. A new CC slot is now being made available, but even if ITV do win it for the ITV NC, sooner or later we'll have the same scenario with ITV5! The News Channel needs a guaranteed slot otherwise improvements are pretty pointless!
On to improvements. The ITV NC would be helped enormously if it had it's own studio. Nothing to fancy is needed, just a room with a desk and a screen - I'm thinking something like the long curved screen as used for the Big Brother eviction shows earlier this year. That could then hang behind the desk and form the background to stories and be used for live interviews.
However, even without a new studio they can make improvements by just switching studios at the top of the hour, rather than changing presenters midway through the hour.
The schedule - trying to be realistic, so hence it's not a 24-hr schedule, but there are a few tweaks, especially to the afternoon and prime-time line-up:
05.30 ITV Morning News
6.00 GMTV News Hour
With signing, moves from ITV2
7.00 ITV News at Breakfast
With Andrew Harvey and Lucy Alexander
10.00 Live with Alistair Stewart
(from London Tonight studio)
Also with Lucy Alexander
12.30 ITV Lunchtime News
With Nicholas Owen and Nina Hossain
1.30 ITV News Network Lunch
NEW
Presented by one of the LN presenters, linking live to regional newsrooms and bringing the top local stories this lunchtime.
2.00 ITV News Afternoon Live
NEW
Rolling news throughout the afternoon, with Leyla Deybelge and Chris Rogers.
5.00 ITV News
(from 2nd studio - either CSO or new NC studio)
NEW
It's basically a rival to Live at Five, with the aim to make ITV NC the first place viewers turn to when they are back from work. Felicity Barr is the main presenter, alternating with Steve Scott. Includes live links to a few regional newsrooms.
6.30 ITV Evening News
With Mark Austin and Mary Nightingale
7.00 Evening News Extra
ENE, presented by one of the EN team, is extended to an hour with additional features including a sports bulletin (with Felicity) and a link-up to some regional newsrooms "UK Today" style.
8.00 ITV News
Felicity Barr (or Steve Scott) returns with an hour of rolling news.
9.00 ITV News at Nine
(from 2nd studio)
NEW
Katie Ledger presents the news channels very own flagship bulletin.
9.45 ITV News Sport Extra
NEW
A daily sports bulletin, with Felicity Barr (or Steve Scott)
10.00 ITV News Network
With the BBC and Sky 10pm bulletins generally being more international based, the ITV NC offers it's nightly regional round-up programme as a genuine alternative.
10.30 ITV News at Ten Thirty
With Mark Austin (and sport with Felicity Barr - or Steve Scott of course!)
11.00 ITV News
Katie Ledger presents an hour of rolling news
12.00 ITV News Nightline
NEW
Katie Ledger presents Nightline, a new nightly look back at the top stories of the day and look ahead at the stories of tomorrow as the first editions of the morning papers hit the shelves.
1.00 ITV News Nightline
Nightline is designed to be repeated throughout the night, so recorded as more of a news magazine show than a traditional news bulletin. Repeats continue on the hour until 4am.
And yes, I know it's not a live overnight service - but until the daytime line up sorts itself out, it's not a priority IMO.
4.00 ITV News Replay
More repeats, but repackaged as another chance to see how the news developed throughout the day. In other words, it begins with a repeat of the Lunchtime News, with repeats of the Evening News and 10.30 bulletin to follow. With ads and regional news cut out, it should all fit nicely into 90 minutes!