It can be tricky tinkering with Hub landmarks, as a growing array of ambitious local developers are finding.

One of the latest, and so far more successful, examples when it comes to making potentially big changes to a classic landmark can be found in Boston’s Back Bay.

The Christian Science Church, with help from a city-appointed neighborhood panel, is considering some significant changes to its breathtaking reflecting pool as it drafts plans for a major new office and residential development on its campus.

Still other Boston landmarks may be in store for some significant revisions as well, once the economy begins to rebound and new development becomes financially feasible again.

These range from a proposed tower that would soar over South Station to budding plans to transform the depths beneath Boston Common into a major parking and transportation hub.

But developing around historic landmarks, especially in a city like Boston that reveres its past, can be risky business, with any mistakes or setbacks likely to be magnified.

Just ask John Hynes, the successful Hub tower builder now scrambling to make good on a so-far disastrous remake of Downtown Crossing’s turn-of-the-century Filene’s complex.

If nothing else, expect some lively debates as changes are contemplated to some of Boston’s best-known landmarks.

Remaking An Icon

“The pool is an icon,” said Marc Laderman, a Fenway activist, of the Christian Science Church plaza’s most distinctive feature, who has been following the church’s plans to redevelop its 14- acre plus campus.

While the reflecting pool is considered a Boston treasure, one had better be prepared for a long walk around if you want to get to the other side.

That would change, though, under plans being floated by church officials and its advisors for a pedestrian bridge across the pool. In fact, there’s even talk about turning the pool, not an inviting spot to hang out during the cold winter months, into an ice skating rink for part of the year.

Of course, there is also a lively debate over where to put the more than 900,000 square feet of new commercial and residential space slated to take shape on the Christian Science campus.

A panel of neighborhood residents, elected officials and local businesses has been meeting for months to talk over possible development scenarios.

Some are pushing for a mid-rise tower by the elegant old Horticultural Society building, where Massachusetts Avenue and Huntington Avenue meet. Others are advocating for a lower-slung, L-shaped structure that would wrap around existing buildings.

Still others would like to see a long low-rise that would stretch down Huntington Avenue, parallel to the reflecting pool.

“I can see a building along Huntington Avenue framing the space better than a line of parked buses, honestly,” Laderman said.

And as the economy rebounds over the next couple of years, you can expect more such debates over how to marry new development with such revered architectural gems.

And they won’t all be so harmonious.

Un-Common Difficulties

In fact, another, likely more contentious, debate is already taking shape over plans that could have a major impact on Boston Common.

The Massachusetts Convention Center Authority is signaling it wants to revive a proposal that would double the number of spaces in the 1960s-era parking garage that sits underneath the Common.

James Rooney, the state authority’s chief executive, envisions the expanded garage connecting with the nearby silver line to become part of a larger transportation network, one that could see conventioneers park in the garage and ride over to the new Boston Convention & Exhibition Center in South Boston.

Despite talk of putting money into improvements to the Common, park activists such as the Friends of the Boston Public Garden appear less than thrilled by the prospect of a giant construction project taking shape there.

You can also expect to hear more from two major tower proposals slated to take shape above or near other Boston icons.

After years of wrangling with everyone from the FAA to Amtrak, a Texas developer finally has the city and state permits needed to start construction on long-delayed plans to build a skyscraper over South Station.

While much depends on how quickly the office and financing markets rebound, actually building the tower could prove tricky, with the station serving as one of the region’s major commuter hubs.

If and when the project finally moves forward, don’t be surprised if some group such as, say, the Aggrieved Commuter Rail Riders of Boston, doesn’t pop out of the woodwork to launch an 11th-hour protest. (As far as I know, such a group does not exist, but my apologies if it does.)

A proposed tower over the Copley Place Mall, shelved when the economy went south, is also likely to resurface at some point as well.

But mall owner Simon Properties has its own historical hurdle to clear, over concerns by neighborhood activists and elected officials regarding the shadows that might be cast over nearby Copley Square.

Certainly the approval process in Boston, especially as it relates to projects near such sensitive, iconic sites, can appear laborious.

Yet if there’s any rule for building around such Hub architectural gems, it’s to make sure you have all your ducks lined up before you kick off work.

A Lesson From Hynes

A stalled project that leaves a big hole in the ground is never the best publicity, but woe to the developer who fruitlessly tears up the cityscape next to a beloved building or historic site.

A veteran tower developer, Hynes appeared to be doing everything right when it came to redeveloping the Filene’s complex, lining up a complex series of city and state permits needed to build around a historic building.

Not long after, the developer started work tearing down an addition to the graceful, turn-of-the-century Filene’s store as he worked to firm up his financing package. It appeared to be a formality at the time.

But his plans to build a modern tower on the site came to a screeching halt when the financial markets crashed and work halted.

There are certainly other holes in the ground across the city and suburbs right now, but none as high-profile as the half-baked looking block in the heart of Boston’s shopping district.

When reporters are looking to do a story now on stalled development projects, Filene’s will naturally top the list.

And as developers start tinkering with various Hub icons, it’s a cautionary lesson they might want to keep in mind before they push forward.