Not sure the World Cup will be "added to" in any other sense than numerically by having more than 10 teams, in fact I'd say you'd just be increasing those 'making up the numbers' from 20% to 33% (2/10 = 20%, 4/12 = 33.33%)
If Zimbabwe could find their feet a bit in the coming couple of years that might change, Bangladesh would have to improve more dramatically than they have in the past decade.
The problem is the odd upset is nice for fans/neutrals, but that's all the better teams who didn't make the QFs this time round are capable of, that is unless the ICC goes with tiers so the smaller teams like Ireland get regular competitive cricket and not just a handful of token ODIs in which they'll probably get beaten mostly with the odd win or decent performance.
That then causes the ICC a headache, do they go with the risky 2007 format with the chance ONE upset could knock a big gun out, and then it meant a lot more mismatches than they'd hoped for, or do they go with the 2011 format and have a lot of mismatches? In a way I'd say Ireland did themselves no favours in 2007, they made the ICC and TV fear that format, Ireland and Bangladesh, and the 2011 format had too many sides who played in a lot of mismatches.
If the ICC do a u-turn, I suspect they will try and format the competition to mean whoever did qualify would get as few matches as possible ie they'd concede to including the extra teams, but only tokenly and probably not quite the participation the qualifiers would hope for.
I don't doubt the ICC and TV want round-robin, the best sides playing in a league format with as close games as they can manage and very few mismatches. While Ireland have won four and tied once in 15 World Cup matches, the breakdown is less what the ICC/TV want to see I'd guess :
WINS
PAK 132/10 vs IRE 133/7
ENG 327/8 vs IRE 329/7
IRE 243/7 vs BAN 169
HOL 306 vs IRE 307/4
TIE
IRE 221/9 vs ZIM 221
LOST
IRE 183/8 vs WIN 190/2
ENG 266/7 vs IRE 218
IRE 152/8 vs SAF 165/3
NZE 263/8 vs IRE 134
IRE 91 vs AUS 92/1
IRE 77 vs SRI 91/2
BAN 205 vs IRE 178
IRE 207 vs IND 210/5
WIN 275 vs IRE 231
SAF 272/7 vs IRE 141
vs BAN/ZIM/HOL : P4 W2 L1 T1 (Won 50.00%)
vs The rest : P11 W2 L9 T0 (Won 18.18%)
A good record against the weaker teams, makes more of a case for tiered cricket, while they generally got tonked against the better sides - even in their second World Cup. Three of their wins were batting second, two chasing sizeable totals and one of those against Test opposition and the other against fellow 'minnows'
Ireland also had a trend I identified in the 2011 World Cup of collapsing badly from five down.
So are Ireland wanting the World Cup to be their arena to improve, or perhaps I could be cynical and suggest it is all about the $$$$$$ IF they really want to improve they need to garner support for expanding Test and ODIs between World Cups to include the sides supposedly just outside and knocking on the door of Test status. If it is about the $$$$$$ then they are going about it exactly as any money grabbers would