Richard Allen is out and William Clark in. But President Reagan did not fully resolve his foreign policy development problems - nor did he touch his parallel domestic policy organization troubles - by replacing national security adviser Allen with longtime California friend Clark.
According to experts here on White House organization, as well as administration insiders, the heart of the problem was not Mr. Allen, his missteps, or even the reputed animosity in his dealings with Secretary of State Alexander M. Haig Jr. The issue was the administration's habit of focusing on a few priority themes on the one hand, and responding to crisis situations on the other, leaving a ''gap'' in systematic foreign policy development in between.
The feeling here is that a heavy burden of proof has been put on Mr. Clark's shoulders - in trying to fill the gap, his skills as an in-house negotiator may not be enough to offset his inexperience in foreign policy.
In broad terms, the exchange of Clark for Allen preserves the continuity of the Reagan campaign team in the White House. It admits no new foreign policy luminary with the candlepower of a Henry Kissinger or Zbigniew Brzezinski. Mr. Reagan remains the administration's chief foreign policy light - a situation preferred by his top aides.
A strengthened national security post for Clark leaves Vice-President George Bush, currently ''crisis manager,'' freer for his national speaking tours. It will also free him to make plans for his own political future.
The exchange of Clark for Allen broadens the top staff triad of Edwin Meese III, Michael K. Deaver, and James A. Baker III into a ''quadrad.'' Mr. Meese loses authority over foreign policy. But for the time being at least he retains title to domestic policy development - with Martin Anderson, his chief aide, criticized as ineffective but expected to endure. With Clark in the White House, Mr. Deaver will find it easier to leave this year as he reportedly plans. And Mr. Clark could at some point become an alternative to Mr. Baker as chief of staff, a post he filled for Reagan in California.
''Clark is a good politician, able to work with people who are abrasive,'' says Charles F. Doran, Johns Hopkins University foreign policy expert. ''That's useful. But the President already has three people like that. They don't need another Baker or Meese. They need really competent foreign policy advice from somebody the President has confidence in. The problem with Clark is that his knowledge of foreign policy is minimal. The President may be confident about Clark, but his absence of knowledge about foreign policy is very troubling.
''They've added a fourth adviser closest to the President, whose purview again is domestic affairs.''
An administration official makes a similar point: ''The President's replaced a mediocre fellow with somebody who doesn't have a great deal of foreign policy background. There's nobody other than Haig - who everybody thinks has a good foreign policy background but personality problems - with the vision to see where we are going, with a plan, rather than react crisis by crisis, or Poland by Afghanistan.
''You can't blame Meese, or Allen either.
''The flaw that causes these decisions is the hesitation to bring in strong personalities and let them run their own show. In order to bring in a Kissinger . . . you've got to be willing to have some heads roll, some battles going on. At least you will have someone who keeps an eye on the ball a few paces ahead.''
''What's interesting is where this puts the secretary of state,'' observes Mr. Doran. ''He really had an opportunity to consolidate his power in the way he wanted to in this period. He hasn't succeeded. Once again he is facing a situation where he has no more direct access than he did before. And he has to share power with somebody who is really close to the President. Haig's knowledge may be sufficient to help him out. I'm just not sure how much Clark can provide day-to-day practical background information to the President about policy.''
''They're unwilling to add a new player to the group,'' says an administration insider who has campaigned for Reagan. ''They don't like to fire people. They want people who are comfortable with everybody else and who won't overreach. The campaign team continues. The group that won the presidency is still intact. Also intact is the group's flaw that they don't want particularly strong people around.''
''There is an advantage to not bringing in people from the outside,'' says Stephen Hess, Brookings Institution expert on White House organization. ''The President has to want to take information on a regular basis from an adviser. If Dick Allen did not have that role because the personal chemistry wasn't right, it appears Clark has that required relationship.''
To Hess, the Clark-Allen exchange ''sounds like the sort of fine-tuning that should be expected'' at the one-year point in a new administration. Giving Clark direct access to the President is seen as a major and needed organizational improvement.
Clark's challenge in overcoming the President's predisposition about policy and organizational matters may prove formidable.
''What really is happening here,'' says Doran, ''is one has a President who is not concerned about the details of policy at all. He delegates these matters, is willing to tolerate a lot of inefficiency and incompetence on the part of others, and in fact only deals with issues when they become either a crisis or are so central to the whole program that he in fact has gotten involved.
''The problem in foreign policy is inconsistency, and this creates enormous unease among those expected to implement policy because they don't get the signals they need from the President.''