First Atapattu was as much a manufactured opener, who at most was No 3 that got asked to open as we had little options.
Personally I think there is quite a few players trying to put their hand up to replace Jayasuriya and Atapattu. The first come to mind are off course Vandort and Tharanga, who will be given first shot at the openers spot. Then the next in line ATM is Warnapura who the selectors have already considered as potential opener in Tests and in ODIs through Sri Lanka A. He is very much a middle order batsmen but probably has a lot better technique to open then other options especially in Tests.
Then you have Dilruwan Silva, would has decided to make a big move in his career and play for big club (Colts CC) to increase his chances of selection and force himself to play with big boys in Division One. I don't think he has the technique to cope at ODI level, but atleast his making himself work on it by platying better bowlers week in week out.
Then you have Dilshan he has made a big statement this season with his intent on taking over from Jayasuriya by moving to opener for Bloomfield. His started off brilliantly with 180 in first game off the season on fairly tricky pitch where most batsmen struggled. There is talk that he going to move to the top in FC as well, as he wants to shown the selectors he can bat in all conditions and all situations. Very much a Watson/Hodge move, but his got the runs to back him up this move, leading run scorer to date in List A.
Tharanga Paranavitana is the probably the guy that will get the spot long term. Probably the most talented opener outside Upul Tharanga and his got runs in domestic cricket to back him up, just needs to score runs for Sri Lanka A. With an average of 37 odd, his got one of best averages in FC cricket in country. But his lack of runs outside his home ground SSC have counted against himself, as well as his relative slow scoring rate, s/r of 60 in List A.
Ian Daniel is another option, his probably has the best technique out of all the openers and would have to a good options for Test Cricket, if he can string together a good season.
But the guy that has been earmarked as future mainstay at the top of the order is Mahela Udawatte. His started to score some consistant runs for Sri Lanka A. He has his best start to the season so far with 239 runs @ 40 in 6 OD games. At 21 he is the youngest out of all the realistic options and will be the guy to watch out for.
With regard to Kapugedera he has indicated that he doesn't want to open the batting and prefers batting down the order. When it came to U19s the only reason why he opened was cus no else could do a decent job, as shown by the performances of the openers in the last Under 19 WC. His shown some positive signs at No 5 and I think he should be given a go there. Also Chamara Silva couldn't score a run in domestic cricket at No 3. So I can't see why anyone would want him to open the batting. If you look deeper at domestic cricket in Sri Lanka, there are plenty of options so I don't see the need to force Silva or Kapugedera to open, when they both prefer batting down the order.
Really I don't think it is all so bad on the opening front. Vandort and Tharanga will probably do the job until Udawatte is ready and then Vandort will probably move down the order. Dilshan and Tharanga will do a job in ODIs, again until Udawatte is ready then Dilshan will either be finished or moved back down the order. If those guys don't work then I reckon Paranavitana will be able to do the job in Tests.
In Tests I actually think we have a fair bit of depth. In ODIs I think we are a bit short due to fact most guys are pretty slow scoring, Sangakkara may have to step up and open if Dilshan doesn't work and Udawatte takes longer then expected to be ready for International Cricket.
It is going to take a while before some of these excel at International level, but most are in their mid 20s now. They have been waiting a while for Atapattu and Jayasuriya to retire and get a chance for 2-3 years. So they are primed for a chance at this level and I would be surprised if they don't make the most of it. I'm actually looking forward to see who steps up and not really worried if they fail as there is someone else to take their spot who can also do a job. There is depth around the opening position, it just they haven't been able to been given a chance to show what they got.